MAKING A ROCK GARDEN
HOUSE & GARDEN
It is the intention of the publishers to make this series of little
volumes, of which Making a Rock Garden is one, a complete library of
authoritative and well illustrated handbooks dealing with the activities
of the home-maker and amateur gardener. Text, pictures and diagrams
will, in each respective book, aim to make perfectly clear the
possibility of having, and the means of having, some of the more
important features of a modern country or suburban home. Among the
titles already issued or planned for early publication are the
following: Making a Rose Garden; Making a Lawn; Making a Tennis
Court; Making a Fireplace; Making Paths and Driveways; Making a
Poultry House; Making a Garden with Hotbed and Coldframe; Making
Built-in Bookcases, Shelves and Seats; Making a Garden to Bloom This
Year; Making a Water Garden; Making a Garden of Perennials; Making
the Grounds Attractive with Shrubbery; Making a Naturalized Bulb
Garden; with others to be announced later.
Making a Rock Garden
In Europe, particularly in England, the rock garden is an established institution with a distinct following. The English works on the subject alone form a considerable bibliography.
On this side of the Atlantic, the rock garden is so little understood
that it is an almost unconsidered factor in the beautifying of the home
grounds. There are a few notable rock gardens in this country, all on
large estates, and in more instances some excellent work has been done
on a smaller and less complicated scale either by actual creation or by
taking advantage of natural opportunities. But
Now a rockery, with all the good intentions lying behind it, is not a rock garden. It is no more a rock garden than a line of cedars planted in an exact circle would be a wood. A rockery is generally a lot of stones stuck in a pile of soil or, worse yet, a circular array of stones filled in with soil.
A rock garden, above all else, is not artificial; at least, so far as appearance goes. It is a garden with rocks. The rocks may be few or many, they may have been disposed by nature or the hand of man; but always the effect is naturalistic, if not actually natural. The rock garden's one and only creed is nature.
Rock gardens are of so many legitimate—in other words, natural—types,
Here, in a nutshell, are not only the natural variations of the rock garden, but the inspiration. No rock garden worthy of the name has ever been created by man that did not depend upon a study of those that nature has given the world in prodigal abundance. There were the why and the how of it all, and man simply saw and made use of his observations.
The advantages of a rock garden are, primarily, an element of
picturesqueness that nothing else can provide, and the possession of a
place in which can be grown some of the loveliest flowers on earth that,
if they flourish at all, will never do as well in the ordinary garden as
in conditions more or less approximating their natural habitat. Also it may
be made a
The best site for a rock garden is where it ought to be. That is a sad truth, for it eliminates some homes from the game; but useless waste of time will be saved if this is recognized at the outset. First cast your eye about and see if you have a spot where a rock garden would look as if it belonged there; that is the supreme test. If one does not seem to belong there, give up the idea philosophically and take it out in enjoying the rock gardens of other people.
As a rule a rock garden should not be near the house; it is something
savoring of the wild that does not fit in with most architecture.
Exceptions are when the
Nor should the rock garden, any more than the rockery, be in the lawn
unless it is depressed and therefore out of sight, or mainly so, from
the level. The depression may be a natural or an artificial one, it may
be a brook with high banks or it may be a sunken pathway. The edge of a
lawn is better, a corner of it is better yet, and preferable to either
is a bank sloping down from it. The bank on either
Trees need not be altogether avoided; sometimes they are essential to the pictorial effect. It is not well, however, to place a rock garden near very large trees. The drip is bad, especially for alpines, and the greedy roots not only rob the plants of nourishment but are very apt to dislocate the stones.
Somewhere just outside the real garden is the best place; then it is
only a step from one little world into another that is altogether
different. If the rock garden leads to a bit of wood, either directly or
through a wild garden, there will be all the more to rejoice over. The
more irregularity the site has, or suggests, the better; a rock garden
not only should have no straight lines, but it is not well
What constitutes a good site is well illustrated by one of the existing
American rock gardens. The place is large, and in the rear of the house
the grounds are level for a considerable distance and then drop with a
fairly steep bank to a driveway, below which another terrace leads to a
meadow. Instead of being continuous, however, the bank above the
driveway is broken by a little glen, seemingly leading nowhere, but
actually an entrance to both the rear lawn and the formal garden. In
this glen is the rock garden, or rather the main part of it. Though
bounded on the north—it runs east and west—by the formal garden and on
the south by the lawn, the rock garden can be seen from neither of
these, nor from the house. It
Thus far the assumption has been that the rocks have to be gathered up
from various parts of the place or brought in
A single boulder, a few scattered rocks, or a rocky bank can be converted into a simple rock garden without moving a stone. A little judicious planting and the transformation is complete.
A rock garden with water is a rock garden glorified. Wherever possible,
without injury to the main scheme, the garden
Spring is the best time to make a rock garden. When the important matter of the proper site has been put in the past, a definite scheme must be planned. Upon the definiteness of this scheme, much of the success of the rock garden will depend. Here desire will have to be subservient to the situation. It is not so much what you want as what is best in the circumstances.
Do not attempt slavishly to copy the rock garden of some one else. All
the money in the world would not create an exact duplicate for you,
since nature has made no two rocks precisely alike. Study them, of
course; get all the ideas you can. But study first, and most,
Measure carefully the space at command, and then lay out the plan on
cross-ruled paper. Call each of the little squares a square foot and the
labor will be made easy. Next, figure out a good entrance, and, if
possible, an equally good exit—the one invisible from the other.
Then comes the selection of the rocks. Usually the rock close at hand, perhaps on the very grounds, will answer every purpose. If you are not fortunate enough to own any, very likely there is more than one townsman who will be glad to give you all the boulders and smaller rocks that you want, if you will only remove them from spots where they are not desired. The cost of removal, even in the case of boulders of fair size, is not great.
Barring quartz rock, which does not look well, almost any kind of
natural stone may be made use of to the best
Boulders may run up to several tons in weight. Where none is readily
obtainable, one can be simulated by ingeniously combining a few small
ones and concealing the joints by the planting of such things as
stonecrops in earth—which, save in rare cases of sheer necessity, is
If the site is level, the next step is to change all that—first on paper. Unless the lay of the land is all right at the outset, the configuration of the rock garden must not depend wholly upon the upbuilding; there must be some excavations, but no depressions deep enough to catch and hold water just where you will want to walk.
Aside from the path levels, building begins with the rocks, not with the
soil. This is a highly important point. Place the boulders first; they
are the big effects. Aside from that, the heaviest work will be out of
the way. Then start in with the outlining base rocks. These should be
placed with the largest surface to the ground and should vary in size.
It is not essential that the lowest rocks should
When the paths and outer margins have been thus defined, scatter more rocks over the intervening surface, placing them fairly thick but not close together. Next, fill in with soil, packing it firmly and ramming it hard into every crevice. If it fits in with the day's work, it is not a bad plan to water the rock work well in order to pack the soil, and when resuming the labor on the morrow, to add more soil, well pressed down, before proceeding with the second layer of rock.
This second layer should have the rocks placed with the front edge
slightly back from that of the lower row in order to form a slope,
though an occasional overhang may be fashioned if required for a certain
plant known to abhor a drip from above. The construction then proceeds
At no point between two stones should the layer of soil be less than two
or three inches thick after being packed hard. If an upper stone is
likely to bear down too heavily and crush the plant roots, this may be
avoided by placing small stones here and there in the layer of soil. The
roots will work between these stones, but there must be a continuous,
though not necessarily straight, soil run from the front of the rock
work to the solid filling
Rocks calculated to simulate a natural stratification ought to be laid on an incline for proper drainage. Such pieces of rock may also be employed sparsely in wedging, and in the making of the so-called "pockets."
These pockets are of prime importance in the construction of a rock
garden. They hold the only considerable spaces of soil and are the chief
means of colonizing plants, thus providing for pronounced color effects.
They should break the slopes and be irregular in size, shape, and
distribution. The large ones may be easily subdivided by small stones
when the planting is done if a further separation of species is
desirable. The soil must slope a little from the top, so that there will
be no standing water.
The drainage of a rock garden is of vital importance. There must be
plenty of moisture stowed away behind the rocks against the heat of
summer, but all excess must be carried away. The garden should drain
naturally, as the hills do. If any doubt exists, make a drainage bed of
The soil should be a good loam with a little peat, and stones varying in size from a mustard seed to an almond. A little manure may be used, but it must be old.
There are two ways of planting a rock garden. One is to do all the crevice planting along with the building, and the other, of course, is to defer everything until the rocks are in place and the soil thoroughly settled.
The former plan is a singularly appealing, as well as practical, one.
There is something fascinating in finishing completely a part of the
work as one goes along. The practical advantage lies chiefly in the fact
that by this method good-sized plants may be firmly established in
crevices at the very outset. The soil in that case should be put part
way in the crevice and packed down. Then some loose soil sprinkled on
top, and the
As a matter of fact, the planting plan cannot be too thoroughly thought
out in advance. At point after point it dovetails with the structural
plan, which must accord with the requirements of what may be called the
more difficult rock plants—the alpines, some of the ferns, and those
plants that fit in well with rock work but demand more than the ordinary
The general idea is that all the soil shall be concealed, not
necessarily at the moment of planting, but at the end of one or two
seasons' growth. Unless you are a collector, variety is of little
importance. The main thing is that there shall be beauty as a whole, a
few marked seasonal effects of color with massed bloom and some green
the year round; the garden must never be bare at any time, as nature
will show you. Plants clustered here and
Study at the same time the form of the plants that are to be used; some
quickly resolve themselves into a carpet, some never get beyond mere
tufts, some always grow straight up, some prefer to hang down, and some
have foliage that is evergreen or nearly so. To be more specific, one
Tall plants, like the foxglove, may sometimes be used, in a small group,
at the end of a bay on the level of the path; but they are best placed
behind the rock work, as a background, or as dominating features of the
entrance or exit of the garden. At the entrance or exit such bold plants
make a good bridge between the rock garden and the outer grounds.
Spreading and trailing plants should be
Obvious considerations are that plants with a decided hankering after moisture or shade should be favored in the matter of location, though it is astonishing how adaptive many of them are.
Do not plant the weak next to the strong. Unless you are a gardener of
Finally, do not forget that planting is not the end; it is only the beginning—of planting. So long as the rock garden exists there will always be planting. Normal mortality will necessitate some, there will be thinning out, and time will suggest additions and more or less rearrangement.
And with the planting goes on the continual care, much of which can be
done in the course of the daily walk in the garden, and therefore the
loss of time will not be felt. Water in case of a real drought, but use
a sprinkler, and do not stop until the ground has been soaked to a depth
of a few inches. Mere surface watering is bad enough in the ordinary
garden; in a rock garden it is a fatal error, as the growth of roots
near the top of the soil
Go over the garden thoroughly once a year and all the time keep a sharp lookout for weeds. If the soil is heavy, top-dress with grit in the fall. Grit is good for rock plants. Stone chips placed around a plant will prevent too much dampness lodging about the collar in winter. Watch out for weak spots after very heavy rains.
So many plants are suitable for a rock garden that the range of choice is bewildering. In this, as in the laying out of the garden, advisability takes precedence over pure personal desire, though, very fortunately, it is often not difficult to make the two go hand in hand; a little intelligent thought helps a lot.
To the beginner, no better advice can be given than that which applies
to the picking out of the rocks—use the material which is close at
hand. This is not, by any means, a mere suggestion to follow the lines
of least resistance. It is far more. In the first place, there is always
an endless amount of beautiful and suita
So far as plants native to the immediate neighborhood are concerned,
their value to the rock garden of the average person with limited time,
who is not obsessed with the idea of growing the rare and curious,
cannot be overestimated. And they are so many; more than most
For a Connecticut rock garden the Greek valerian (Polemonium reptans)
must be purchased, unless a neighbor can spare some from his collection
of old-fashioned flowers; there it belongs in that category. But why
should you of Minnesota or Missouri deny so beautiful a flower a place
in your rock garden, simply because you have only to go to the woods for
it? The English enthusiast brings home primroses from the Himalayas,
From ferns alone, or from only plants of shrubby growth, a most beautiful native rock garden may be made. And adding small flowering plants, or excluding all else, there are limitless opportunities. It goes without saying that A's rock garden in Maine will not be like B's in Louisiana; but there is no law compelling it to be.
Among the common wild flowers of the East that take on unexpected new
beauty when transferred to the rock garden are the celandine
(Chelidonium majus), strawberry (Fragaria Virginica), cranesbill
(Geranium maculatum), toadflax (Linaria
Annuals as a class are not desirable for the rock garden; for one thing,
the care of renewal is too great. Biennials are almost as much care, but
in each case there will always be exceptions that are a matter of
individual preference. Few, for example, would have the heart to reject
the dainty little purple toadflax of Switzerland (Linaria alpina),
just because it is a biennial. The main dependence, however, must be
placed on perennials—the plants that, barring accidents, last
indefinitely. These should be mostly species; if horticultural, do not
use the bizarre—Darwin tulips, for example, or the Madame Chereau iris.
Nor, with rare exceptions, should double flowers be used. A double
daffodil looks horribly out of
The easy rock garden plants, where the material is not taken from the
wild, are to be found in most of the large hardy gardens of the East.
Some of them are natives of Europe or Asia, and more than is commonly
suspected are at home in other parts of the United States. Among the
best of these for carpets of bloom are Phlox subulata, Phlox
amœna, Aubrietia deltoidea, maiden pink (Dianthus deltoides),
blue bugle (Ajuga Genevensis), white bugle (Ajuga reptans), woolly
chickweed (Cerastium tomentosum), creeping thyme (Thymus serpyllum),
dwarf speedwell (Veronica repens), Saponaria ocymoides, alpine mint
(Calamintha alpina), and pink, white, and yellow stonecrops (sedum).
All of them fairly hug the ground. There are other
Several of the primulas give a like effect if the planting is close—as
it should be in a pocket. The best are the English primrose (Primula
Taller plants that may be worked in, oftentimes best with only a single
specimen or small clump, are autumn aconite (Aconitum autumnale),
Yucca filamentosa, leopard's bane (doronicum), single peonies (either
herbaceous or tree), German, Japanese, and Siberian iris, as well as the
yellow flag (Iris pseudacorus), single columbines, Anemone Japonica,
Hemerocallis flava, Sedum spectabile, Dielytra spectabile,
Dielytra formosa, Jacob's ladder ( Richardsonii),
fraxinella, Anthemis tinctoria, single Campanula persicifolia,
Campanula rapunculoides, Campanula glomerata, globe flower
Of the lilies, Lilium Philadelphicum, L. elegans, L. speciosum, and L. longiflorum are all desirable, and they thrive in partial shade, though in Japan L. elegans will be found standing out from the rocks in full sunshine. For peering over into the rock garden, rather than being placed in it, L. Canadense, L. tigrinum, and L. superbum are recommended.
The pick of the low shrubs are the charming Daphne cneorum, which
flourishes better for being lifted above the ordinary garden level, and
Azalea amœna. The latter, however, should be so placed that its
trying solferino does not make a bad color clash. Rhododendrons and
mountain laurel fringe a rock garden well,
Single roses, the species, fit in well where there is room for them. Good ones are R. setigera, R. rubiginosa, R. Wichuraiana, all rampant, and the low R. blanda. The roses would better be at or near the entrance or exit, or far enough above the rock work not to ramble over small plants.
The plants in this list cover all seasons and vary somewhat in their soil and moisture requirements. But the variation is nothing beyond the ordinary garden knowledge. Most will do better if their preferences are considered, but none is apt to perish with average care.
Alpines, as a class, would better be left to the amateur with the time,
money, and disposition to specialize. Most of them
A wall garden is a perpendicular rock garden. But whereas a rock garden is of all things irregular, a wall garden has regularity. The wall need not be a straight line; it is better that one end should describe a curve, and rocks at the base may give it further irregularity. Yet it can never quite lose the air of man's handiwork. The prime object of the gardening on it is to reduce this air to a minimum.
The way to make a wall garden is to build a dry wall of rough
stones—that is, a wall without mortar. Instead use soil and pack it
tight in every crevice as well as behind the stones, which should be
tilted back a little to carry water into the soil. This tilting may be
Although the face of the wall in either case may be strictly
perpendicular, it is
In planting also, follow the same rules. It is better to plant as the
work progresses. Either plants or seed may be used. If it is seed, press
carefully into the soil in the front of the crevices. Small seed may be
mixed in thin mud and this plastered on the soil. For a tiny crevice
make a pill of the mixture.
The range of reliable plants that do not call for special care is not
great so far as the crevices are concerned. All the stonecrops, the
house leeks, Arabis albida, red valerian (Centranthus ruber),
aubrietia, Alyssum saxatile, snapdragon, wallflower (Cheiranthus
Cheiri), Kenilworth ivy, Viola tricolor, Dianthus plumarius, and
Dianthus deltoides are all very ser
If the dry wall is already made, the crevices can be plugged with soil if care and patience are used. Even a cemented wall is not hopeless; here and there the mortar can be chiseled out and an occasional small stone should be removed.
A wall garden has these advantages over a rock garden; it is more easily constructed, it is of practical use, and it is sometimes a possibility where the other is not.
Neither the water nor the bog garden is dependent on rocks. Either or both, however, may just as well be an adjunct of the rock garden. They solve the wet spot problem admirably, permit the culture of native water lilies, orchids, and numerous other beautiful plants, and certainly contribute their share of picturesqueness. If water is lacking, it may often be introduced at little expense.
In most cases it will be found that some cement construction is
necessary, but not a bit of it should show. This is easily managed by
building a cement shoulder on the sides of the pool or stream a little
below what will be the level of the water, and then setting rough stones
on that. A
Dispose the rocks very irregularly, but they may be so few as to be mere notes. Avoid stagnant water, and if mosquitoes are feared introduce some goldfish. They like mosquito larvæ.
Water lilies and sagittaria—one plant will do if the pool is small—in
the water and near it, but not in standing water, Japanese iris, yellow
flag, globe flower, and Lythrum roseum are good selections.
The bog garden simply reproduces bog conditions. As a rock garden adjunct it may be a small spot with the perpetually moist and moss-covered soil in which the native cypripediums and pitcher plants flourish. Eighteen or twenty inches of suitable soil, a mixture of leaf mold, peat, and loam, in which has been stirred some sand and gravel, must be provided. If an artificial bog, the bottom may be made of cement or puddled clay.