Chapter 1: Root-pruning (1)

This is often the first thing you do for a plant that is to be grown bonsai-style. It is a procedure that is repeated regularly if your plant is to have a long life. Dwarf trees and shrubs are root-pruned so they will fit their small containers, or to make room for fresh soil when they are repotted, or to keep the root system in balance with the growth above soil that is being restricted. Pruning also keeps the roots compact, near the surface of the soil, and vigorously young. Removing old, woody roots encourages the growth of fine new ones.

When seedlings, rooted cuttings, and small newly purchased or collected plants are made ready for their first bonsai containers, they are not immediately root-pruned in a severe sense. Any roots that are dead should be trimmed off and long taproots should be cut back at least one-third. Otherwise, it’s a matter of trimming off the root ball with as little disturbance as possible, just enough to fit the container.

After they have been established, plants are root-pruned when they are repotted. When roots are crowded and completely cover the soil in a close mesh, it’s time to repot and root-prune. For some plants this may come once in a year, for others once in five years.

Hold the base of the trunk in one hand--your left hand if you are a right-hander. Use a dull-pointed pencil (the Japanese use a chopstick) and loosen the soil around the outside. Pick away about one-third of it if the plant is established, somewhat more on younger plants. When you have finished, the soil ball should be, roughly speaking, one-fourth smaller than its container. Then, with sharp scissors, cut away all the loose root ends which you have removed from the soil. This is rather drastic surgery, although not like removing an arm and a leg of a gardener, because the plant or shrub has the happy faculty of growing new roots. However, it will need special care and protection until it is back on its feet again. Bonsai plants are root-pruned and returned to the same container year after year. None of this making each container one size larger each time the plant is moved into a new house. That’s for house plants per se.

_Soil_

Potting soil for dwarfed trees and shrubs is particularly important. There is so little of it in small containers. In general, it should provide good drainage and aeration while also holding a certain amount of moisture. On the specific side, soil contents and textures should vary to meet the individual plant’s needs.

If your plant happens to have been dug locally, take along a supply of local soil. If you happen to have purloined the plant from a neighbor’s woods, purloin a little soil. It’s no more of a sin to have stolen a sheep than half a sheep. In our neighborhood it is a standing joke about how many plants, flat paving stones, etc., we swipe from each other. If you have been honest enough to have bought your plant from a nursery, ask their advice on the soil. If they are not smart, although most of them are, get the reference book down off the shelf and find out whether the plant craves a mixture that is sandy, rich in humus, acid or alkaline, fine or coarse. You have a baby on your hands. Treat it right and it will award you with adulthood in bonsai. Neglect it and it will curl up and die. Mix your soil as you would a baby’s formula. Remember, babies cry when the formula is faulty; plants can’t. They silently pass away.

_Potting and Repotting_

I am frequently asked how often an established tree or shrub should be repotted. It depends, first, on how fast it grows. A willow may need this attention twice a year, a conifer once in five years. A general rule is to repot flowering and fruiting plants about once a year, most deciduous varieties every other year, evergreens every three to five years. But don’t follow that schedule too literally. If a tree begins to wither or look weak, if its color turns sickly and it shows no sign of growth, if its roots are so packed they hump up the soil, root-pruning and repotting are often the “shot in the arm” that can save it.

The most favorable repotting seasons vary with types of plants and the climate. Again, it’s a good idea to consult some authority or reference book. In general, and in most areas, it is safe to repot evergreens, deciduous foliage varieties, and summer-or fall-flowering types in early spring before new growth begins. As for spring-flowering plants, repot immediately after flowering; for fruiting types, in early autumn before cold weather sets in.

As a side light, it is possible to use watertight containers minus drainage holes. That is rather desirable when a plant is to be displayed on finely finished furniture in the house. The container should be a shade larger than usual so that, in potting, a corner area or space along the side can be left empty and the soil sloped down toward it. If there is any standing water it will show up in this section. Just up-end the container and drain off the excess water. In the process make sure that the plant is not also drained off or disturbed. But that you will know from plain common sense.

If a pot has drainage holes, I always make sure they are partially covered with crockery or aluminum window screen so the soil will not sift down and clog the holes. To insure even better drainage, I screen the first layer so that it is coarse and granular, put a little soil on top, and then set the plant in place. In oblong or oval containers, the trunk is usually one-third of the distance from the end and a little behind the center line. Of course, that depends on the shape of the containers. In round or square containers, the plant is usually centered.

When planting, fill in the soil gradually. Use a pencil, or if you have the true Oriental feeling, a chopstick, to tuck the soil in tightly around the roots. Whatever you use, be sure to eliminate any pockets of air. Roots don’t like it. As to how tightly you pack it, that depends on the type of plant and the texture of the soil. If your soil is built up around the edges and sloped toward the center, you will have a depression that will hold water until it can seep down to the roots below. Unless you have some particular plan or design, finish off the surface with a ground cover of moss, or perhaps a layer of gravel. Moss is not only an added attraction but functions as a mulch and delays the evaporation of moisture from the soil underneath.

After repotting, soak the soil thoroughly, and soak the container, which is probably dried out. Mist the foliage and remove any debris such as fallen leaves and petals. Then keep the plant sheltered for several weeks until it is re-established. Remember, it has had what a human being would regard as a major operation.

Some of the most appealing bonsai plants are grown with their roots around a rock of interesting and harmonious size, shape, color, and texture. Soft, porous tufa is especially good for this purpose because you can cut and shape it easily. You can hollow out cavities and crevices, just the place for roots to grow. Any rock should have a stable base. Please don’t let it tip or wobble.

For this sort of planting, select a healthy plant in vigorous growth with roots long enough to reach down the side of the stone. Prune away any roots that are too short or dead, and remove the soil from the others. Set the base of the trunk in place on top of the rock and arrange the roots so that the tips reach down and can be buried in the soil in the container. Both roots and plant may need to be anchored in place for a while; that is, until they can stand on their own.

Such plants naturally need special watering and protection for the first few months, perhaps even for a year or so. You can help them along by rubbing soil into the roots after they are fastened in place, or covering them temporarily with a thin layer of moist moss. Should you do any repotting, be careful not to loosen the roots on the rock.

Recently, in the home of one of my Redding neighbors, I saw a bonsai arrangement that pretty much follows what I have been describing above, except that it goes it one better. This gardener, in the search for the “right” rock, had walked miles along the stone fences that divide fields, woods, and properties in our area. Eventually she found a beautifully weathered specimen with a large pocket in the top. This she filled with a rich, moisture-holding soil mixture, encasing some of the roots of her bonsai in it. Then she set the rock in water in a shallow container to help keep it moist. Someday I am going to defy the snakes that are said to lurk in the cracks and crevices of our rock walls and see if I can’t find something to approximate what my neighbor discovered. I hope it will have a few lichens on it. That would be a crowning touch of age and antiquity.

_Shaping and Pruning_

These are the techniques, says one author, that “make bonsai culture an art.” That statement alone is sufficient reason to invalidate just about all of the specific rules. But there are others--the wide variations among plants and types of plants, plus the personal element, the variances in personal tastes and degrees of artistry.

Instead of trying to cover bonsai pruning and wiring in complete detail (there are many excellent books on the subject), I’d rather speak from personal experience and set down the basic principles as I see them and have used them. By following these principles--not word for word, or too literally, but with your own creative ingenuity and imagination--I feel you can shape a true bonsai plant, or adaptations in the bonsai manner.

First, let’s define the objective--a miniature tree or shrub with every part in perfect scale, the line and design of trunk and branches clearly outlined and not forced or distorted but naturally picturesque. If you start with a very small plant, a seedling, or a rooted cutting, the choice of shape and design is mostly up to you. But more mature plants almost always suggest their own form. A trunk may be slightly twisted, a branch slightly bent, the leaves or needles heavier in one area than another. You simply carry on the illusion in as natural a manner as possible.

In pruning, the first step is to remove all weak or dead wood, and any unwanted branches that cross unattractively or perhaps go off in the wrong direction. Then, you decide whether more branches should be pruned away--to reveal the basic form of the tree in general or the trunk in particular; to lighten the over-all effect; to help create the desired symmetrical or asymmetrical shape. If the plant has been root-pruned, the top should be pruned proportionally. Top growth and roots should always be kept in balance. Growing tips are pinched or cut back to encourage the development of side shoots, or merely to keep the plant in dwarf proportions.

From here on, pruning depends on the plant and the planned design. Slow-growing types may need trimming only once a year; others need constant attention. Any undesirable or excess growth is best removed while the plant is still young so the operation won’t leave an unsightly scar. Needles that are too long can be cut down to proper size from time to time. Leaves that are too large and heavy can be severely thinned. Because fruit that is too plentiful can weaken a dwarfed tree severely, some of it should be removed.

At repotting time you may find a few roots immediately under the soil surface that have enlarged to such a good size they can be exposed above the soil. If possible, spread them out slightly so they form a swelling base for the trunk. This is fun, but takes a bit of doing. You don’t want to end up with something that resembles an unanchored telegraph pole with leaves at the top.

Stems, branches, and trunks are trained by wiring them and then bending them along the lines you desire. Wiring is best done in the spring. New growth is just starting and the older woody parts are more supple and pliant. If the soil is left dry a few days before wiring, the wood will be even easier to work with. You can use ordinary galvanized wire. If you happen to have only copper wire, try annealing it. Hold it in a fire and then plunge it into cold water. The weight and strength of the wire will depend on the size of the trunk or branch with which you are working. Be careful not to get a wire that is so stiff you can’t bend it easily.

As to the actual process, first fasten one end of the wire. Perhaps you wrap it around the trunk, or better still, stick it deeply into the soil. Next coil it rather loosely around the branch that is being trained and fasten it again at the end. Now, using both hands, bend the wired branch in the direction you want it to go. Be firm, but be gentle and cautious. Ease up if the branch shows signs of breaking or being injured. Don’t hurry the job. If necessary, only bend it a little the first time. Bend it a little more the next week, and the weeks after that. If you are tempted to rush, stop and think of the bonsai creations you have seen on display at flowers shows. Usually you will have seen a card that says the creation is fifty or more years old. Be especially careful with old hardened growth or plants with tender bark that is easily bruised or broken. Most important, once you start to bend a branch, don’t change your mind and try to bend it back the original way. It will almost surely die. Plan before you act.

Depending on the type and age of the plant, wires may be left in place for six months, a year, or even more. However, watch carefully for signs that the plant is being choked or disfigured due to heavy growth.

There are also some easy ways to train parts of plants without wiring them. Branches can be pulled down to a horizontal line by looping soft cord around them and hitching it to the container. They can be made to hang down, or weep, by hanging weights at the tips. If you want to straighten a trunk, tie it with something strong, like raffia, to a straight bamboo stake. To narrow a wide fork between two branches, pull them together with raffia. To widen a fork, prop it apart with a light wooden wedge.

_Location_

Whether you have a collection of bonsai growing on tables or benches, or perhaps just a few plants, in summer give them outdoor growing quarters where there is a free circulation of air. Full sunlight is good except during the hottest weeks or months. Be careful to protect them against hot, drying winds and burning sun, which they cannot stand. Being in small containers, excessive heat or dryness is dangerous. We had some old bamboo shades that once enclosed our porch which were good protection. We also had some lath screens which came in handy. Lacking either, hang up old sheets or sections of burlap. You can help by keeping it moist with the garden hose.

_Watering_

Many factors determine how often your plants should be watered--age, type, size, how recently they were repotted, size of root system, and the usual climatic conditions such as temperature and humidity. About the only concrete thing I can say is that your plants will resent neglect, and will show it. Newly potted plants should be kept moist constantly until they begin to make new growth or show other signs that they have recovered from pruning and transplanting. For plants that are established, the ideal is limited moisture in the soil. Don’t keep it so wet that rank growth is encouraged. And please beware of rot. That is one of the most evil of evils when you are too generous with the watering can. At the other extreme, the soil shouldn’t be so dry that the plant wilts beyond recovery. You, as a grower, will have to determine this for yourself. I do it by feeling the soil in the container. If it feels moist to the fingers, no water is needed. Let it feel dry and it probably needs a drink. When you do water, be thorough. Make sure the soil is so completely moistened that the excess water runs out the drainage hole in the bottom of the container.

_Fertilizing_

There is a definite, delicate balance between too much and too little fertilizer for a bonsai plant. Too much food and it grows too large and is loaded with large foliage, flowers, and fruit. If you feed it too sparingly, it will suffer from malnutrition. I most certainly wish I could give you an exact rule to use. I fear no one can. Requirements differ for different plants. All I can offer is a few basic principles. The rest is up to you.

For the first few months after you have repotted a plant in fresh soil, withhold all fertilizer. Don’t fertilize a plant that is weak or sick or approaching dormancy, and don’t fertilize when the soil in the pot is dry. Be alert to fading leaf color, reluctant growth, and all similar signs that a plant is suffering for want of nutrients. These signs may be most apparent during the spring season of most active growth.

Organic fertilizers such as bone meal, liquid manure, or fish emulsion are usually recommended, and should be used sparingly in weak solutions. The purpose of this feeding is to keep the plant healthy but still small, and not to encourage larger growth.

_Insects and Disease_

My bonsai plants are much too precious to take chances with any sort of infection or insect infestation. As a preventative, I use an all-purpose aerosol bomb regularly, according to directions on the label. Constantly I keep a sharp eye for any signs of trouble. Thank goodness, up to now I have had no serious threats, but should they come along, there is a remedy I have used on other plants. I would dip them, container and all, in an appropriate solution, thus making sure it would penetrate every crevice and cover every surface. For outdoor bonsai and the problems most likely to beset plants while in their summer quarters, I have elsewhere discussed insects and diseases of trees and shrubs. Those general principles also apply to bonsai.

_Winter Care_

In areas where freezing temperatures are the rule or, as here in Connecticut, where temperatures are much lower, dwarfed potted trees and shrubs should spend the winter where the soil in the small containers will not freeze. We have a tight cold frame where we plunge the pots into the soil, then cover everything with straw and salt hay. Those who happen to have an unheated porch, one that is glassed in, but where the temperature does not go below freezing, have a good winter quarters. But, be careful, don’t let the soil in the containers dry out completely. Keep a watchful eye.

After that warning, may I offer another. Please don’t coddle plants by keeping them warm in the house or greenhouse. A cool period of complete rest is often very beneficial, or even a touch of frost.

_CHAPTER 10_

MINIATURE GARDENS
IN THE LANDSCAPE

A picturesque surprise on a gently sloping, sunny bank could be a wind-blown mugho pine beside an outcropping rock that’s lightly draped by a sprawling cotoneaster, with colorful sempervivums clustered at the base. Or in the light shade at the base of a clump of white-barked birches, there could be a group of dwarf rhododendrons displayed against dark, humus-rich soil or a pine-needle mulch. On a patio or terrace, it could be a contemporary grouping of low, fluffy juniper, perennial lavender, and water-polished rocks.

These are miniature gardens--not complete landscaping plans for small properties, but appealing plantings that often pop up in unexpected places and bring beauty into otherwise unusable or undecorated areas. They’re gardens because, by definition, they are groups of plants that achieve an effect a single plant could not create alone. They’re miniature gardens because they occupy small space, and because most of their plants are of miniature proportions. Properly designed and executed, they’re equally effective in large grounds or small, with contemporary suburban homes, in informal settings, and even on estates with traditionally formal landscapes.

There’s a special enchantment in these miniature gardens. The eye is attracted by their modesty and restraint, and by the utterly natural way they seem to suit the scene. Each plant is seen intimately, in close-up; its character is revealed in each small detail. And in these gardens the creator can express his individuality so easily; seldom does a design even resemble the one next door.

Miniature white poppies featured in a tiny garden beside an
outcropping of rock]

Part of the appeal, of course, lies in the charm of miniature plants--tiny annuals and perennials, small or slow-growing evergreen and deciduous trees and shrubs, available in amazingly wide variety if you take the trouble to find them. There are also frequent opportunities to use inert objects with special effect. Small gardens can be designed as settings for works of art or products of the hand-craftsman--ceramic bowls and urns, authentic wrought-iron grilles, wood carvings, statuary, sundials, pools, even fountains and waterfalls. Or a garden may be designed with a background of well-placed rock, a tree stump, or a piece of driftwood. A bench, arch, gate, antique hitching post, or well-house may inspire a miniature planting. Inanimate ground covers such as gravel are often a definite part of the design.

In some ways miniature gardens are easier to design than, for example, standard items such as flower beds and foundation plantings. It’s easier to achieve originality. Mistakes are usually small and easily corrected. On the other hand, really good design is more critical than in large plantings where space can swallow errors and provide lucky effects. In miniature, even a minor defect shows up immediately, and may be a major calamity.

DESIGNING MINIATURE GARDENS

The first and basic requisite is an idea the garden is to express, a theme for the picture it is to create. The objective may be to embellish some neglected nook, disguise an unattractive corner, feature an unusual plant or art object, soften the lines of a small pool and blend it with its surroundings. Once the goal is set, it is pursued without deviation. For example, a featured plant is kept dominant--not necessarily in size, but always in visual importance--and everything else is subordinate. A pool planting does not become so elaborate that the beauty of mirrored reflections or rippling water is lost.

In both conception and execution the design for a miniature garden should be in harmony with its surroundings. Nearby buildings may call for certain harmonious lines and proportions. Land contours, and constructions such as walls and steps, may dictate size and shape. The architecture of a house and its landscape has a style that should not be violated.

Our Connecticut landscape demands informal or naturalistic design in no uncertain terms. Straight lines and formal geometric shapes would be not only out of place, but practically impossible to achieve. The land’s slopes and rises call for beds with flowering curves. Points of interest such as massive lichen-trimmed boulders, gnarled old trees, or a winding stream are sublimely situated by nature’s unerring instinct for what looks right. We’ve merely cleaned them up and made the most of them.

For not-too-modern houses built on regularly shaped, level lots, some sort of formal design is easier to achieve and much more suitable. In the traditional style, elements of equal size and weight balance each other. There is strict adherence to a predetermined pattern. Identical beds may make a formal dooryard garden, for example; matching groups of plants may ornament opposite sides of a gateway.

For houses of contemporary architectural style there are gardens of contemporary design, often featuring paved areas and patterns with distinct angles and curves. Plantings are based on the tone, texture, and form of the plants themselves. The object of interest is off-center, balanced by a larger area of subdued importance.

Miniature gardens should be not only in harmony with the style of the surroundings, but also in proper proportion. A birdbath with miniature roses planted underneath can look lost in the center of a spacious lawn, but could be in correct scale for a niche or arch in a brick wall.

Simplicity is extremely important. The smaller the space, the faster it will take on a spotty, cluttered look when crammed with too many different plants. The smaller the space and the plants, the more care and thought should be given to combining various types, forms, textures, and colors for best effect.

In addition to aesthetic principles, there are practical aspects to designing miniature gardens. Any site should be checked for cultural and environmental conditions that favor healthy plant growth. Is a wall so high it throws too much shade for sun-loving plants? Is an area too exposed in winter for questionably hardy plants? Is the spot so low that water collects and stands in the soil, making it suitable only for bog plants?

Think of the work of maintenance, too. Use ground covers instead of lawn in areas so small you can’t move a mower around. Avoid fast-growing plants that need constant trimming and pruning. Don’t use plants that require a lot of protective spraying or dusting unless you have time to keep up with the job. A healthy dwarf barberry is more attractive than a neglected, sickly rose.

MINIATURE BEDS, BORDERS, AND ISLANDS

There are a number of ways to use small-scale versions of the familiar mixed-flower border. Annuals and perennials can be selected for continuity or succession of bloom, and arranged so that colors harmonize, textures contrast, and carefully placed taller spikes or spires provide accent and relieve monotony. In the background there may be dwarf evergreens or flowering shrubs, a low fence or wall, the side of a tool house or other small building.

Use miniature flower borders to add interest to tiresome areas such as long, narrow strips between the house and boundary line of the lot, or along a service walk. Use them at the edge or in corners of small lawn areas--never scattered through it--or at the base of low foundation plantings. Use them as visual space dividers between driveway and front yard or entrance to the house.

Miniature beds are also effective at one side of a breezeway, at the edge of a terrace or patio, or beside the back door. If they are raised slightly, perhaps the height of just one brick, the small plants are nearer to eye-level and their full beauty is more clearly revealed. I’ve also seen a tiny cutting garden, by the back fence, that was as colorful and pretty as any border.

Whenever there are walks, there are spots for miniature beds--in the diamond-shaped points where two walks join; as little islands along the curves; in the angles where corners turn. Or use small formal beds for dooryard plantings.

The intimate dooryard garden, by the way, is enjoying a revival. Instead of advice to keep flowering plants away from the front of the house, we’re encouraged to plant little gardens that can be seen from the picture window and also will make the house more attractive to passers-by. These don’t replace foundation plantings and front-yard landscaping, but supplement them in a small way. And the small gardens help relieve the monotonous sameness of many modern house fronts.

All kinds of corners are obvious sites for ornamental treatment with tiny gardens--architectural corners between front entrance and house wall, between one wing of the house and another; the back corner of a lot where, perhaps, a small tree is a focal point or background or where, if you’re fortunate, a small stream winds its way across your property.

On almost any grounds there are natural nooks that seem to be made for miniature gardens up and down the sides of informal steps, at the top or base of low walls, in a patch of soil at the foot of a high-branched tree.

Landscape or architectural focal points can often be enhanced by little gardens--gates, bay windows, sundials, the mailbox, a birdbath, or a well. Little pocket-handkerchief gardens are built right into patios and terraces. Little creepers planted in crevices between paving stones make a miniature garden of their own.

_CHAPTER 11_

MINIATURE ROCK AND
WALL GARDENS

Anyone who can live and garden in a place like our part of Connecticut without going overboard for rocks and rock-loving plants has more self-control than I. My bewitchment began one Sunday afternoon when, the weekend’s weeding done, I strolled up toward the small wild-flower plantings in “the point.” Just beyond the garage, before the trees began to cut off the sun, I stopped to glare at an ugly, erupting mound of soil and stones that had frustrated our every attempt to make this area more attractive.

I was pondering the monstrosity, when I noticed an intriguing detail. A partly submerged rock poking its head out of one side of the mound had the same color and patina as a snub-nosed piece sticking out the other side; and the lines of stratification were on the same slant. Could these be opposite ends of one continuous rock formation?

Five wheelbarrow-loads of rocky debris later, we had uncovered a beautiful boulder, perfectly placed so that its lines led gracefully into twin trunks of a wind-blown birch. It was a boulder with ancient age and character, artistically chiseled by the elements. And it said “rock garden” as plainly as any landscape plan.

This five-foot-long discovery may not be miniature; and the naturalistic kind of planting it inspired is neither practical nor suitable for many home grounds. But it was my introduction to rock plants, and to how effectively rocks and plants combine; and it led me to create and watch for rock gardens that _are_ miniature, practical, and suitable for all kinds of grounds. Sometimes I think these are the most enchanting little gardens of all.

If they are to look like anything better than a pile of stones, miniature rock and wall gardens are not composed of miniature rocks. They simply contain fewer, perhaps somewhat smaller, rocks than average gardens; and they occupy far less space. These small plant-and-rock compositions brighten nooks and corners where other plantings would seem out of place.

By their nature, most rockery plants are miniature in height, foliage, and flower. Alone or combined with miniature bulbs, the smaller perennials and annuals, and the tiniest shrubs and trees, they invite close-up enjoyment of their daintiness in these small plantings. Rocks and rock-loving plants have a perfectly natural way of blending and contrasting, each bringing out the best qualities in the other.

Although they’re of different design and construction, rock gardens and dry walls are usually planted with the same or similar plants, and given similar care. Paths, pavements, and garden steps are close kin. But pools and water plants, even though they are often included in rock gardens, are a separate subject, and are covered in Chapter 12.

ROCK-AND WALL-GARDEN DESIGN

“Cemetery,” “penitentiary rock pile,” “collection of geological specimens”--these and other unflattering phrases have been used to describe what a rock garden should not be. This eliminates the artificial rock-studded circle in the center of a lawn, rocky slopes with nothing to back them up, isolated paths and steps that have nowhere to go, stone-stuffed piles of loam with no conceivable excuse for being where they are.

What a rock garden should be, is an integral part of the landscape, completely at home and in harmony with its surroundings, and having a sound reason for its existence. Except for a few functional affairs such as walls that retain terraces and steps that climb banks, their purpose is mainly ornamental. Neither rocks nor plants are featured at the expense of the other. Both work together to create the picture--the plants to add brightness, vitality, and life; the rocks to help provide favorable growing conditions and a naturally suitable background for their display.

Designs for these gardens can be, as for others in the landscape, formal or informal. The fixed geometry of walks, walls, and raised beds in formal pattern are seen less frequently. But this is a type of rock garden that might be placed advantageously in even the flattest, barest suburban lot where naturalistic plantings and rocks look out of place. If you long for a rock garden, try something like this in either classic or contemporary style.

Informal rock gardens must, above all else, look convincingly natural, as if the glaciers might have placed them. This is equally important to a cluster of bulbs at the base of a single, half-sunken boulder; the arrangement of rocks and plants on a small slope; or the series of rocks that line a winding path. Builders of ambitious rock gardens are often advised to study the nearby countryside and use it as a guide.

_Designs for Naturally Uneven, Rocky Land_

This type of terrain makes a natural setting for rock and wall gardens of all sizes, shapes, and contours. Generally, the design is informal and naturalistic. I don’t know whether it’s really easier to work out such designs in miniature, or whether I merely think it’s easier because that’s the kind of land I have to work with. So far, we’ve never disagreed with Nature about the placement of a rock outcropping, for example. The few we’ve uncovered and cleaned up have almost told us what and how to plant.

A small existing slope or bank is a perfect site for a composition of rocks and rockery plants, or, if you prefer, a retaining wall between the two levels with plants grouped at the bottom or top, or planted horizontally in the cracks. Or consider a series of ledges that create small, irregular terraces.

A slope or grade may be the perfect place for informal stone steps, with, of course, a path leading up to them and away. Colonies of small plants look well on either side, with, perhaps, very miniature evergreens at both sides at the top. Cracks in the steps and a walk can be planted with small carpeters.

If you possess a small stream, gulch, or ravine, by all means consider a little rock garden along either side. If you’re fond of a gnarled old stump, see what a few rocks and plants might do at its foot. Where your driveway curves, try a small rock garden. Before you fill in and flatten out a small depression, or level off a small knoll, find out how it would look as a small “island” rock garden.

Corners like those formed by an old-fashioned “stoop” of a country cottage sometimes make effective frames for miniature rock gardens. But in general, informal designs usually fit best out in the grounds, away from angular architectural lines.

Raised flower bed copied from an old English garden]

_Designs for Level, Rockless Grounds_

Here there are fewer existing, desirable locations for rock and wall gardens. But for the sake of enjoying the dainty plants, and of marking your garden with originality, you may want to create a site. It is possible to dig out a “natural” depression or build up a slope, if it’s skillfully designed--and if you can get rocks that don’t look foreign and far away from home. Or dig down a foot or two to make a formal or semiformal sunken garden, the beds raised and held in place by a dry wall with crevices to plant in, and flagstone walks.

Corners sometimes offer possibilities--a far corner, where there is a background of trees, fence, or wall; or a front corner where the lawn slopes slightly down to the sidewalk. Or there may be a place near the patio for a tiny pool in a rocky setting.

A birdbath, sundial, or shrine that’s a focal point in a small garden can sometimes be embellished with a small rock garden at the base. So can the edge or corner of a raised patio. Terrace pavements with cushions of thyme rooted in the crevices are enriched with color, fragrance, and texture. The lines of stark steps are softened and the appearance mellowed by crowded clumps of fat sempervivums. Wherever you can find reason for a rock wall, or even a row of rocks laid horizontally and only a few inches high, you can plant it with rockery plants at top, bottom, or in between. In the artificial settings of many suburban lots, semiformal walls separating two levels of lawn or supporting the edge of the family living area are very suitable substitutes for rock gardens.

MINIATURE ROCK AND WALL PLANTS

One of the main virtues of rock and wall gardens is their individuality--they don’t look like other gardens, or even like each other. But commonplace plants such as bedding petunias can cancel this distinctiveness in a minute. If you use annuals at all, get less ordinary varieties and use them sparingly, for temporary color in a bare spot or over the dying foliage of spring-flowering bulbs.

The plants that look best with rocks are those that grow naturally among them. Hundreds of rock-loving plants are available, and more hundreds of alpines from rugged mountain heights. Only the easier alpines are included here, the most adaptable to more luxuriant climates and soil, the least likely to pine for their rigorous, high-altitude homes. Tricky types from above the timber line are left to the dedicated collector.

Saxifraga seedlings--a natural rock-loving plant]

Nurseries and catalogues of rock-garden specialists are so full of distinctive and delightful miniature plants that my first reaction was blissful delirium. And after I acquired as many enticing items as I could, my second thought was: These gems are too little known and grown. So I began to sort out some that might flourish in our small perennial borders. With favorable conditions of drainage and air circulation, a number of rockery plants have already made themselves at home in other, rockless gardens.

Most miniature bulbs are effective in rock gardens, and some miniature perennials--not ubiquitous types, and not those that spread voraciously by runners. Miniature shrubs and trees are indispensable in rock gardens of all sizes--to give variety, contrast, and substance; to act as accents; to create boundaries or backgrounds. Use them with restraint. Place spreading, wind-swept types at the top, bushy shapes down lower, upright exclamation points at the very bottom. Make sure they are in scale with the rocks, the plants, and the garden as a whole.

Select all kinds of rock and wall plants for their effectiveness of form, texture, and color in the complete design. And this repetition is important and unavoidable. Select varieties that naturally like, or will adapt to, the cultural conditions like sun and soil type you have or can provide.

MINIATURE ROCK GARDENS

For setting a few rocks into the side of a handkerchief-sized section of slope, or building many more into a garden in a good-sized corner, there are a few guiding principles that will help make sure you are happy with the result. Most important, have your design as complete as possible before you start to build. A sketch drawn to scale is a valuable visualizing aid. Then, make your construction solid and substantial, and favorable to plant growth and health.

If you have a choice of exposure, face a sloping rock garden toward the north or northeast, so it will get enough summer sun but not so much that it dries and cooks. Shrubs and trees in the background should not create dense shade in the garden, nor drip moisture on the plants and steal nourishment from their roots. Drainage is extremely important in selecting a site. If the subsoil is packed and clay-like, you can either replace it, make it more porous, or select another spot.

What kind of rocks to use and where to get them depends on the part of the country you live in. Anything that’s indigenous to an area is first choice, always. Limestone, sandstone, fieldstone, porous tufa--native rocks “belong” as no artificial or imported rock ever can. If your land is not blessed (or cursed) by plenty of rocks, you can sometimes collect them near rivers, mountains, or abandoned quarries, or where a new road is being blasted through. Whether you have them, collect them, or buy them, all the rocks in one garden (or on the same property) should be of the same general type. Varicolored geological specimens are seldom attractive.

Consider each rock’s characteristic color, texture, size, and shape before you decide where to place it, or whether to place it at all. Even in the tiniest rock gardens, tiny rocks look ridiculously salt-and-peppery. Start with rocks of substantial size, in keeping with the size and contour of the garden; use smaller ones where they fill in effectively.

Naturally worn and weathered rocks look more natural than freshly chiseled surfaces; irregular, angular forms are better than uniformity. Rocks with stratified layers suggest ledges and cliffs. Glacial boulders or “hardheads” are not good in formal patterns. Use them naturalistically, in varying sizes, arranging them with studied carelessness as if they’d been scattered haphazardly and then left.

Avoid overcrowding with so many rocks that the plants are overshadowed by the debris. Place rocks as they might lie naturally, partly buried in the soil, the tops smoothed over by the elements, and so solid that they don’t wobble when you step on them.

_Construction_

Perfect drainage, so that water cannot stand around the roots and crowns, has been called “the most important need for all alpine plants.” The selected location (raised or sunken) and composition of subsoil and topsoil can either contribute to good drainage or deter it. In small gardens it’s not too formidable a job to install a system of drainage tiles, if necessary, or to add gravelly sand to subsoil to make it more porous. Easy insurance in any rock garden is to start with several inches of rather coarse gravel or rubble as a bottom drainage layer.

Any topsoil that is removed during construction should be saved carefully. If you can pile it in the center of a tarpaulin or piece of strong burlap, it can’t be scattered and lost; and you can also mix it with any additives with pleasurable ease. Simply pile on the peat, leaf mold, sand, or other ingredients; then, holding opposite corners (you may need a helper to hold one corner of a large piece), pull it back over the soil pile and fold it over the other end. Repeat this, from opposite ends, until the materials are thoroughly mixed.

The first rocks are usually set at the lowest part of the garden, partly sunk in soil or otherwise made extra-sturdy and secure. Build up from that point, arranging rocks with their broadest surfaces at the bottom, all lines of stratification horizontal or on the same slant. Each rock should slant slightly inward and downward, to catch moisture and encourage it to run into the soil in the garden.

Provide plenty of soil for spreading roots, and a minimum depth of eighteen inches or more. Plants in shallow pockets may be stunted and will certainly dry out too fast during droughts. Whether or not you plant as you go depends partly on your agility. Don’t crush the first plants under your feet or knees as you set rocks and plants above them. It’s often faster and easier to spread out roots and make soil firm around them before the next rock is set in place.

_Planting_

Set plants as deep as they were planted before; no deeper (danger of crown rot) and not too shallow (they may dry out). Tuck them firmly in cool, moist, rock-shaded soil. Keep the soil constantly moist until firm new growth shows that the roots are established and growing.

Rock-garden plants are seldom suitable for planting in neat rows or geometric patterns. Tiny, slow-growing types are arranged in groups of three or more; one or two spreaders per planting spot will do. Don’t crowd these plants. Give them room to develop and for air to circulate around them, and to display their charms at their best. Provide private quarters for the smallest gems, away from hearty growers that might overpower them. Keep color combinations and contrasting textures in mind. Set trailers where they can droop over stones. Place those that like moisture low in the garden; their roots keep cool in the shade of rocks.

As a finishing touch, after the rock garden is built, planted, and thoroughly watered, cover all soil surfaces with a mulch of fine gravel or stone chips. Work it up to each crown, under prostrate stems. Aesthetically, this gives a neat, well-groomed look and ties plants, rocks, and setting into one coherent picture. Functionally, the chips absorb heat and keep soil cool and moist, lift small, low leaves out of mud and water, discourage slugs, protect crowns against rot, and firmly discourage the intrusion of weeds.

MINIATURE WALL GARDENS

Any small section of low wall--brick, cement, stone, or concrete--can be the background for a miniature garden. But it is in a dry wall, built of stones without cement, that many small rockery plants best display their jewel-like perfection. Planted horizontally, with their roots in pockets between the rocks, they make a vertical rock garden of glowing colors and fascinating foliage textures.

For small, low walls, and those in somewhat formal settings, thin-layered rock such as slate or shale is usually preferred. Irregularly shaped fieldstone or other rocks of native origin are used in more natural, informal designs. Any lines of stratification are, of course, laid horizontal and parallel to each other. Another good rule to go by is: The smaller the wall, the smaller the rocks.

_Construction_

Low walls (two feet high or less) usually do not need a foundation layer sunk below the frost line. They can be started at, or just under, ground level. But they must be set solidly on a firm, wide base--two feet wide, for example, for a wall two and a half feet high. Set the largest stones and complete the lower layer first. Tilt each rock slightly backward and downward so soil won’t wash out of pockets, water will run back to plant roots, and the heaving pressure of frost won’t thrust the rocks out of place in winter. A guide line of string or wire moved up with each new layer will help you keep the construction level.

The wall should slant slightly in toward the bank behind it, and usually grows more narrow as it goes up. Each layer is made absolutely solid before the next is applied. Set each stone so that it is completely steady, and rests on parts of two stones beneath it. This distributes weight evenly, avoids crushing plant roots, and prevents unattractive and impractical long, vertical cracks created when joints coincide. Use small, flattish rocks to fill chinks under large stones and make them steady.

Behind the wall, as you build, firm in a goodly layer (one foot thick is usually recommended) of topsoil that has been enriched and aerated to promote drainage. Roots will reach back here for water and food. As you ram soil into pockets, make sure it reaches all the way back to this layer. Unless all the soil is made very firm, it may settle and the stones may slide out or into the bank.

At the top you can leave some pockets for plants, or plant them just behind the wall. Cover cracks at the top with flat stones, so water won’t wash out soil.

_Planting_

If you can remember not to damage plants at the bottom as you’re working above them, set the plants in each layer as you build. It’s easier then to make sure the roots are firmly embedded well back into the soil. Plant sparsely; leave plenty of room for growth and spread, and plenty of uncovered wall surface to contribute pattern and texture to the picture. Space the plants at irregular intervals, never in straight lines either horizontal or vertical. Water thoroughly, making sure the layer of soil behind the wall is completely moist; and keep it moist at least throughout the first growing season.

PATHS AND PAVING

Many little rock plants will make soft cushions and carpets, with their roots in crevices between pieces of paving, and also in stone steps. They’re very low-growing and very hardy, and usually spring back resiliently when stepped on. It’s important that acid-loving varieties not be planted near cement, which sometimes neutralizes or alkalinizes the soil. And, of course, the situation should provide the amount of sunshine and moisture the plants need.

The simplest kind of informal path or paving for an informal patio consists of flagstones or slates set in the ground, the top level flush with the surface of the soil. Plants are spaced irregularly in cracks between the stones. I’ve seen one path of old millstones laid this way, the plants rooted in the center hole.

Bricks create a more formal pattern, either laid on a bed of sand or set into a foundation of concrete over gravel. The popular “crazy pavings” can be odd pieces of either brick or stone arranged in any conceivable pattern and laid in mortar. In any such solid constructions, planting pockets should be scooped out before the concrete sets hard; or a chunk of wood can be inserted to hold the space open.

Give the carpeting plants as much good soil as you can, and keep them moist until they are growing well. Occasional trimming will stop them from growing straggly, and keep them neat, compact, and in a pretty pattern.

PLANTING AND CARE

Planting times vary according to climate and season of dormancy. In warm areas it’s almost always late fall. Where winters are rugged, it can be during brief semidormancy in early September, but it’s safest in early spring when severe frosts are no longer likely and favorable weather blesses plants at the height of their annual growing power. In temperate sections spring-flowering varieties can be planted from mid-August through October, others in spring.

Lemon thyme and ivy showing results of being trimmed and kept
neat

_Mr. and Mrs. Alex O’Hare_]

Strong, healthy, pot-grown plants can be planted throughout the season in almost all areas. They transplant easily, with little disturbance and shock. In fact, whenever we acquire plants during the fall, we keep them in their pots or pot them up, and protect them in the cold frame during the winter. One of my favorite and most knowledgeable rock gardeners tells me that he always pots tender or difficult plants, and keeps them potted until their roots are fully developed, before he sets them out in the garden, no matter what the season.

_Soil_

Providing the proper soil is vitally important to rock-garden plants, and particularly to alpines. They’re naturally dwarfed by the rough conditions in their native mountain areas. But when they move down to our comparatively lush climates and longer growing seasons, they respond to a too-rich diet by growing too tall and rangy, with too few flowers, and they lose their charm. They do need some nourishment, of course. And they are extremely sensitive to soil textures and drainage conditions. Heavy, soggy soil causes them to rot quickly. Soil that lacks organic matter dries out too fast.

Because of climatic and other variations, I hesitate to set down any “ideal soil mix” for these plants. Instead, I suggest a basic formula that can and should be varied according to the aridity or rainfall in your area, the size and location of your rock or wall garden, the composition of your garden soil, the availability of some ingredients, and the personal preferences of the plant varieties you want to grow. Here it is:

Three parts fairly friable, fertile loam.

Two parts humus--peat, leaf mold, compost--for lightness and fertility.

Two parts stone chips or crushed rock--perhaps the most important ingredient, to keep soil open and cool.

One part sharp builders’ sand, or the gravelly sand used in mixing concrete, to lighten heavy soil and promote drainage.

If your garden loam is sandy or gravelly, of course, you would increase the proportion of humus. If it’s rich in organic matter, you would decrease the quantity of humus. Very sticky, heavy clay soils are best replaced.

Rock and alpine plants are also particularly sensitive to the acidity or alkalinity of soil. This is measured by the _p_H scale, ranging from very acid _p_H 4.0, through 7.0 at neutral, to very alkaline 9.0. Rock-garden specialists usually indicate the preferred _p_H for the plants they sell.