The Work Of Construction

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 ock 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,

nature--more particularly its ways in your own neighborhood. Anywhere

there is abundant opportunity. Take a leaf or two from the book of the

Japanese gardeners. They are past-masters of the art of making rock

gardens, with a bit of water thrown in. They make use of comparatively

few blossoming plants, but their example is invaluable in the

disposition of rocks with simple effectiveness, in the simulation of

height and distance, in the proper employment of turf, and in the

planting of such small trees and shrubs as are suitable for a rock

garden scheme.



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

outline the main path, which should be as devious as the situation

allows, and, if byways cannot be added, provide for bays, or more

pronounced recesses. Remember that you are not merely to simulate

nature; you are, by a process of compressing much in little, to

epitomize it.



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 advantage. Artificial

stone should be shunned like the plague. Limestone and sandstone are

good materials; granite is better. Granite, however, does not stratify,

and if stratified effects are desired, another stone must be selected. A

good plan is to use more than one kind, but to keep them properly apart.

Weather-beaten granite is excellent material, and, in general, it is

well to have the rock look anything but newly quarried. Pick out some

rocks with a growth of lichen on them, and be sure that this is not

disturbed by the moving.




has a soil pocket to itself. Note the effective background and irregular

crevices]



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

always used in the construction of a rock garden in place of mortar.



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 be slightly buried in

the ground, but that course is preferable.



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

as before, until the desired height is reached. The height is entirely

arbitrary, but some points should be at least as high as the line of

vision, as one of the great advantages of a rock garden is the pleasure

of enjoying some of the typical rock plants without stooping. The rocks

used as fillers should overlap here and there to give strength, but care

must be taken to contrive plenty of long soil runs. Eighteen inches

should be the very least. A plant like the alpine androsace is a tiny

rosette, seemingly requiring no more than an inch or two of soil, but

its roots are likely to be found following an earth-filled crevice in

the rocks to the depth of a yard or so. It is because of this deep

penetration of roots that the soil should be packed so very firm; the

roots must be in no danger of loose soil or of striking a hidden

hollow.




even with soil between, the pressure may be relieved by the use of small

stones. The soil run need not be straight, but it must be continuous, so

that the roots of the plant may find their way from A through to B]



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 of earth. The run should slope downward

slightly.



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.




shallow (A) and deep (B) soil pockets; tilting and wedging of rocks (C);

bridging (D), and perpendicular crevice soil run (E). Two to three

inches of soil between all joints. The lowest rocks are partly buried]



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

eight inches of clinkers before starting to lay the stones.



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.