Evening star., 1942-09-12


alpines, require cool. moist growin
and keep the roots cool while tn
special soil mixture insures drain
age and root penetration (the pur
pose of the humus and sand in tn,
mixture). Rocks standing on ent
might provide more shade than thos
buried in the soil, but they Civ
an artificial appearance to the gar
den and contribute very little mois
ture to the plants.
Rock walls may take the place O
the rock garden where one wishes tt
use them as retaining walls. How
ever, they offer less opportunity fo
the growth of flowers, require NOR,
skill to build, and are more or les
formal in outline. Where space il
limited, however, rock walls art
more suitable than rambling rocl
gardens. On slopes a combination
Of rock wall and rock garden may
be more practicable than a rocl
garden alone
Both rock gardens and rock wall!
require large-sized pieces. of stone
that are more or less fiat. Rounc
stones are difficult to handle anc
because of their shape are more
subject to 'heaving" than are fla
slabs. Rock garden specialists lool
upon the weathered slabs of lime.
stones to be found in stream bed.
as ideal. Other kinds of preferred
stone are weathered granite anc
sandstone, although to be truly
natural rocks native to the ares
should be used. From two third.
to quarters of each rock vii
be covered by the soil
Brightly colored stones are mo-
desirable in the rock garden or fol
the rock wall. They compete with
the flowers for attention rather thar
forming pleasing and inconspic.
uous background. Such stones us.
ually reflect light and tend to bt
hot, whereas suitable stones pro.
vide cool effect as well as a cool
moist situation for the plants.
The moisture that rocks draw anc
hold is highly beneficial to the al
pine" although these same mois
ttIre-loving plants cannot withstand
moisture at the crowns. Thus WI
find that soil mixture that pro.
vides excellent drainage is also nee.
essary to the vigor and health o.
these plants. 1t is for this reason
that most rock garden builders ex.
cavate the soil to depth of IL tt
18 inches and replace it with mix.
ture of sand Il part), compost Of
peat moss g parts, and garder
loam g parts. Stone chips may
be added to the mixture, especially
If lime-loAng plants are to be
grown, then use the limestone chips
The rocks are laid in this soil with
great care to see that there ar,
no air pockets. Tamping is ont
method of accomplishing this; soak
ing with the hose is another. Ii
rock walls, pals are used to preven
settling to the point where plan
roots are squeezed.
In very heavy clay soils a drain.
age layer of cinders or gravel may
be necessary.
Rock walls are ordinarily built il
much the same manner as a rocl
garden with the slope of the wal
being more nearly vertical and thu
soil space between the rocks very
small. Rock walls usually have s
slope of to 3 inches per foot O
height, are built upon a substantial
foundation layer that is LOCATED
below the frost line, and employ
soil mixture containing less sant
but more humus and if available
we1-rotted COW manure.
In placing the rocks either in tn,
rock wall or in the rock garden
special effort should be made to se
that they slope towards tlae bacl
sufficiently to carry rainfall an,
moisture to the plant roots rathe
than away from them This is YER
important. If the rock plants ar
to be deep rooted and able to with
stand drought they must be pro
vided with moisture Large rock
given the necessary slope in suit
able soil mixture is the best wa
to accomplish this
The use of stepping stones in
rock garden Is very desirabl
feature since they serve to encourag
stepping in the proper places. Ex
cept in very small rock gardens,
is desirable for the gardener a
well as visitors to have access to tn
various plant groups.
The variety of plant material avail
able for rock gardens and rock wal
Is extensive and one need only b
limited by the particular situation a
to sun or shade, and personal in
terests. The beginner might we
conflne his first efforts towards tn
growing of the easier and more dc
pendable plants and shrubs. Or
word of caution: Avoid those plant
which tend to take" the rock gal
den, such as gold moss (Sedum sal
mentosum) and the perennial fol
get-me-not (Myosotis palustris
Bulbs and low-growing evergreen
are especially desirable for ear
spring and winter interest.
A mulch of stone chips to hold tt
soil and to prevent dirt from splash
ing upon flowers and foliage +;
well as to help keep the soil CO
Is desirable after planting.
In planning the rock garden it
well to give some thought to
suitable background. Evergreens al
probably the more desirable bacl
ground, although deciduous shrul
are satisfactory in many cases.
background is necessary both f,
protection and as a setting. Roc
gardens can be constructed upc
level ground and in the center
the back yard and not look especial
incongruous if they are given tt
necessary setting and backgroun
Shrubbery and even trees NAV
necessary to accomplish this effec