Planting The Garden
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 l
es 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 plant, with the earth well shaken from the roots, unless
it has a tap root, laid down horizontally with the crown just outside
the edge of the soil. Next spread the roots to follow the soil run; fill
up the crevice with more soil, packed well, and follow with more plants
of the same kind. Use small stones to wedge plants where it appears
necessary. Plants that hang down should be placed in the higher
crevices; this must be all thought out beforehand.
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
garden moisture. The best way is to decide what plants are most
desirable in the circumstances, omitting, as a rule, the difficult or
"finicky" ones; there will be plenty of time to experiment with those
when you have more experience. Make a face plan of the several sections
of the rock work and mark on it where the plants are to go. Use numbers,
each corresponding to a species.
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 single there is a good
planting rule. Colonies, always of marked irregularity, ought to merge
into one another, but they should not so overrun the rock work that no
stones are in sight. Not infrequently some of the best effects are
obtained where more rock than flowers is seen. A boulder, for example,
calls for the contrast of plants, perhaps only a few low-growing ones in
a natural pocket, rather than a semi-eclipse. As a rule, plant one
hundred of half a dozen or so suitable, and easy, species in preference
to fifty or more kinds.
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
plant of _Saponaria ocymoides_ will spread out over four square feet of
soil, and thus fill completely a moderate-sized pocket, whereas to
conceal the same amount of ground three dozen auriculas might have to be
used. The same is true of the white rock cress (_Arabis albida_). So,
too, with a crevice. A single plant of one of the trailing stonecrops
would fill it, perhaps, when a number of rosettes of the smaller kinds
of house leek would be called for.
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 placed a foot or more above the
path level and most plants with tufts or rosettes of foliage. If the
path is broad enough some of the wide-spreading plants may go at the
base of the rocks, but the rule there is to use those of moderate
spread, with a few tufted plants and some that grow upright, but are not
tall, to lend variety. When the path is of flat stones, irregular in
both size and placing, this growth should fill all the soil space--even
between the stones. Such a path will be found more than worth while, and
not as much of an undertaking as it may seem.
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
eternal vigilance, the weak will have the worst of it before you realize
what a mistake you have made.
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 leaves the plants in no condition to stand the
full force of the summer sun.
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.