My woodland rock garden abounds in the shade, for it is nestled among tulip trees, dogwoods, tall oaks, and other deciduous trees. The many rocky outcrops and slopes face various directions and are planted with suitable material to give a natural though well-landscaped appearance.
Much of the stone remains in its original natural position, but some of the smaller outcrops that could be moved were arranged to form harmonious groups and supply deep soil pockets in ninny places.
Choosing Plants For Rock Gardens
In choosing plants, a wide selection was possible for the scope of material for rock gardens is broad and includes shrubby and herbaceous plants and those which grow from bulbs or tubers, and the like.
Dozens of hardy plant families in each group, suited to various exposures and soil conditions, make it possible to obtain a varied collection of attractive plants for any rock garden.
Besides true alpine, material from the plains, woodlands, and bogs may be used. Rock gardening is so flexible that endless pleasure maybe had even through growing a choice collection of small plants in a pot or tray no larger than a handkerchief.
And an infinite variety of larger plants is available to accommodate elaborate rock outcrops in the more spacious home garden. The choice need not be confined to small tidy plants. Absurd as it may seem, rock gardening may be practiced without the use of stone or rock.
It may be applied to woodland, bog, heather gardens, and many other fields grouped under the heading of rock gardening.
The predominance of shade in my rock garden has made it possible to concentrate on the use of American woodland plants and those from other countries that are adaptable to various degrees of shade.
A minimum of sunshine reaches one of the significant outcrops in the late afternoon through the tall overhanging oaks. This outcrop lies between the house and driveway, facing west. Exposed to the southwest, the stone steps always present an attractive appearance.
Foliage In Selecting Plants
There is bloom throughout this area for about two months in spring, but the plant material offers a variety of beautiful decorative foliage later on. Foliage character and growth habit are given as much consideration as the blossoms in selecting plants. After all, we live with the plant for a significant part of the season when it is not in bloom.
At the base of the steps, growing among the gravel and stones of the driveway, is a patch of creamy white Viola striata. Some of these violas have taken old in the step crevices above this and other nearby spots. These violets are self-sown seedlings from plants at the top of the slope. The driveway seems to be a fertile seedbed for many of the other plants.
Viola striata is a native of the eastern United States, accessible and adaptable to many garden locations, and particularly useful as a ground cover in shady areas where there is much space for a rampant plant.
Although it is a tempting violet with many virtues, it is necessary to stress its major shortcoming—the ability to increase by self-sown seed at a great tide. Where there are small choice plants in the immediate vicinity, such seedlings must be weeded out before smothering weaker neighbors.
Used in abundance along with these steps and throughout the garden is Epimedium youngianum var. niveum, the small, white barrenwort. This is another foolproof herbaceous perennial of the barberry family.
Its seed habit is directly opposite to Viola striata, for it is only on rare occasions that it sets seed at all. Propagation is accomplished by dividing the plant in early spring or fall.
Although the epimediums are woodland plants, their garden requirements are variable. They are ideal for challenging slopes in the sun or shade and have the ability to spread utilizing creeping rhizomes. When favored with soil containing leafmold, their increase will be encouraged so that a few original plants can be periodically divided to permit an elaboration in their many garden uses.
The delicate 10″ inch sprays of white flowers which appear in April and May are particularly appealing. The foliage is equally attractive and provides an exciting change of color during the passing seasons.
Another plant bordering on the steps is Iberis saxatilis, the dwarf candytuft. This miniature shrub forms a neat mat of evergreen growth, not over 3″ to 4″ inches high. A native of southern Europe, this species grows best when fully exposed to the suit in well-drained soil.
It is a tidy plant, perfect as a ground cover. Individual plants gradually increase to mats of a foot or more in diameter. It is a desirable plant both in bloom in May, with its clear white flowers, or resplendent in its delicate evergreen foliage the rest of the year.
A miniature form of our eastern hemlock. Tsuga canadensis var. hussii grows next to the little candytuft. This specimen conifer is a compact, slow-growing hemlock of irregular shape and is one of the most desirable of the many dwarf hemlocks available.
Surprisingly, there has not been greater interest in this group of conifers. They are as easy to grow and more attractive titan the stiff formal-looking dwarf spruce (Abies), which is more commonly offered. Hemlocks appreciate a substantial amount of hummus or leaf mold.
Planted in the sun, they form a more compact and shapely tree than when they are grown in a shaded location.
Plants With Smaller Foliage
Another plant that grows along with the steps and in the bordering interstices is the larger leaved saxifrage, Bergenia cordifolia—an accent to the plants with smaller foliage growing around it. Fill-in plants, such as sedum, live in the crevices and shallow pockets and act as ground covers for some smaller bulbs.
Many visitors express surprise at the large variety of choice plant materials available for a woodland rock garden such as this. Under a beautiful dogwood, along one large section of protruding rock, a large colony of Phlox divaricata is graced with a foreground of yellow primroses.
A patch of Primula juliae hybrids takes up the color thread where this group leaves off. These primroses have done remarkably well at the front of a shrub border facing east. Their ability to withstand the drought and heat of summer in this spot has been excellent.
The soil is rather heavy and has a high humus content. Even during the last hot and dry August, there was only an occasional need for watering.
As a result of hybridizing, there has been an increasing array of colors in the Ohne primroses, ranging from white and yellows to reds and blues. Their compact habit of growth results in low and neat masses of flowers with proportionately small leaves.
Where they can be given an eastern exposure, they are highly recommended for eastern gardens for they will endure both the high and low extremes of temperature that prevail.
Plants That Thrive When Exposed to Sunlight
One of the most favored Eastern native plants in this garden is oconee bells, Shortia galacifolia. It has been planted tinder varying garden conditions, and its adaptability is surprising.
Experience has proven that it blooms and grows best when exposed to the west, even when situated on rock ledges with a soil depth of a few inches.
But, much leafmold and peat are incorporated with the loam to increase moisture retention.
Shortia is a plant with many uses and is one of the earliest plants to flower in spring, preceding most other native materials. In the New York region, it is generally in full bloom during the first two weeks of April at about the same time as many small rock garden bulbs such as scillas, chionodoxa, anemone, hyacinths, and species narcissus.
Bulbs In Rock Garden
In referring to bulbs for the rock garden, we touch upon a group that adds considerable color, particularly to the early spring season. One recent addition of the many species in my garden is Al-lium zebdanense.
This bulb is planted in well-drained, gritty soil in a shaded section and has prospered and bloomed Well. It is one of the best white-flowered species, growing to about one foot in height.
The flower has a rather pleasant fragrance and makes a good-cut flower. Like most albums, it increases liberally, and a few bulbs will make a showy display in a couple of years.
It is gratifying to know that an ardent gardener’s array of plant materials is almost endless.
Thanks to the efforts of plant explorers, both past and present, interesting materials are always obtainable, either through live plants or through the distribution of seeds. It is easy to do armchair traveling to the far reaches of the earth, through the plants at our immediate beck and call.
44659 by Harold Epstein