Solomon's Seal in a woodland garden.

In many suburbs and cities, creating a woodland garden means starting from scratch in order to create shade. This is especially true in the city, where most noteworthy vegetation of any kind may be long gone. In the suburbs, too, trees are often bulldozed to make way for development and are seldom replaced.

Many of us may recall growing up during those hot and sultry summer days when the only refuge was under the “umbrella” of a huge lawn tree. You may also recall the mute summer light and often verdant quality provided by your own trees or the neighbor’s. Trees create an indisputable sense of place and enclosure—private or otherwise. They also provide a valuable habitat for wildlife. Trees offer a place to hang a swing, build a tree house or hide behind during a good game of hide-n-seek. And I can still recall vividly the fall splendor of color and luminous quality exhibited by the trees in our yard.

Success with a woodland garden requires some attention to the basic requirements of light, soil, proper plant selection and planting, followed by some general maintenance.

As a first step, take an inventory of what is already growing on the site. Are the trees deciduous or evergreen? Is there an under-story of shrubs? A close examination of existing growth may conclude some desirable species that you may want to save. Conversely, there may be some species not worth saving, thus providing an opportunity to plant some of your favorite species.

Selecting Trees for Your Woodland Garden

Dappled shade and “shadows” created by a stately Sycamore tree.

Choose trees carefully; they will be the largest and most permanent feature of the new garden. The “canopy” trees should be small- to medium-sized deciduous species that perform well in full sun and cast light to medium shade. Ideally, your trees should have seasonal interest, such as mottled bark, showy fruit or strong architectural structure. They should also be pest- and disease-resistant and adapted to the conditions of your site (i.e. hot, dry, wet, rocky soil). In our region, consider using evergreen trees like hemlocks and white pines, which make for outstanding additions to any woodland garden, providing they are protected from full sun and heavy winter winds.

Size and placement are critical. Do not make the all-too-common mistake of trying for an immediate effect by planting too many trees or trees that will eventually grow to over 60 feet tall. To establish a shady area quickly, buy the largest trees appropriate for the space, but avoid overly large trees that will soon become out of scale with your property.

If you choose the appropriate trees for your soil and climate, extensive soil preparation shouldn’t be necessary. In newer developments where the original soil may have been stripped or severely compacted, you may need to remove some of the existing soil and replace it with better soil. Some amending is beneficial for supplying organic matter. Stimulate plant growth by watering adequately—about three times a week until the tree is established. Do not over-fertilize as this can cause weak, floppy growth and/or possibly burn the leaves. Avoid coarse and woody bark mulches; they require vast amounts of nitrogen to decay at the expense of your plants. Instead, apply a top dressing of organic mulches (composted leaf and vegetation) about 2 inches thick, once every two years. Organic mulches decompose over a period of time and improve the soil. Also, a crust doesn’t form on top of the soil, so the water infiltrates freely and deeply.

Shrubs for Shade

A tri-color beech, hydrangeas, ferns and astilbes in a woodland garden.

Some shrubs can also be used to create shade quickly. Plants such as red-buckeye, Japanese spicebush and fringe tree can be trained either as large shrubs or as small trees. If removing the lower limbs does not undermine the aesthetic appeal of the plant, many shrubs can be “limbed-up” when they get large enough to allow shade-loving perennial plants to be grown under them.

Using Other Plants

The major challenge in converting a sunny area to a shade garden is using plants that adapt as the area gets progressively shadier. The plants under and around trees will need to be sun-tolerant until the tree canopy gets large enough. Your best choices will be plants that are adaptable to both sun and shade initially, then switching to shade plants in a few years. If your property is already shady, you can delve right into using shade plants such as ferns, hostas and astilbes.

It is often difficult to plant large trees or shrubs under mature trees because of the shallow, woody roots that can be impenetrable. Too much disturbance to the roots of sensitive trees may damage or kill them. In order to avoid problems and make your life easier, plant small trees and shrubs in the open, root-free zones between mature trees. If you have no choice but to plant within the root zone of established trees, start with smaller, one-gallon sized shrubs and 1- to 1.5-inch caliper trees. Take caution as to not damage the roots of mature trees when you dig.

An Aesthetic Mixture

A woodland garden in bloom.

Some Suggested Plants for Southwestern PA: Trees: Carolina silverbell (Halesia carolina) Sourwood (Oxydendrum arboreum) Serviceberry (Amelanchier canadensis) Sweetbay magnolia (Magnolia virginiana) Pawpaw (Asimina triloba) American hornbeam (Carpinus caroliniana) Shrubs: Bottlebrush buckeye (Aesculus parviflora) Clethra (Clethra acuminata) Fotergilla (Fothergilla gardenii) Witchhazel (Hamamelis virginiana) Sweetspire (Ita virginica) Mt. Laurel (Kalmia latifolia) Spicebush (Lindera benzoin) Arrowwood (Viburnum dentatum) Perennials: Flowering anemone (Anemone hybrida) Goatsbeard (Aruncus dioicus) Wood’s aster (Aster divaricutus) Turtlehead (Chelone obliqua) Heuchera (Heuchera americana) Cardinal flower (Lobelia cardinalis) Wild blue phlox (Phlox divaricata) Meadow Rue (Thalictrum rochebrunianum) Grasses & Ferns: Plantain sedge (Carex plantaginea) Hakone grass (Hakonechloa macra) Switch grass (Panicum virgatum) Ribbon grass (Phalaris arundinacea) Maiden-hair fern (Adiantum pedatum) Japanese fern (Athyrium nipponicum) Wood fern (Dryopteris erythrosora)

Design considerations are critically important when creating a woodland garden from scratch. A garden with a generous mixture of deciduous and evergreen shrubs, vines, groundcovers, bulbs, perennials, grasses and ferns is stimulating and dynamic. This type of garden will maximize interest throughout the year and give your garden structure during the winter. Exercise constraint, however, or the result could be a hodge-podge effect and lack cohesiveness. Resist the temptation to crowd plants together and allow them sufficient room in which to develop and grow.

In the woodland garden, the bulk of the bloom is in the springtime, so plants with attractive foliage and varying textures, shapes and forms are a must for interest in other seasons. For the greatest impact, group plants together that bloom at the same time. Plants with variegated or golden foliage can brighten the garden.

Next try to add some unpredictability. The joy I feel while hiking through the woods comes from the anticipation of the unknown—that sense of wondering what I will discover just ahead. Add stone paths, for example, that may dead-end into a bench, or the revelations of specific or unique plants. Remember to emulate nature by installing plants that appear seemingly random. I like to add log pieces, old trunks or other woodland features similar to what one may see in the forest.

Once you have planted your garden with thought and inspiration, sit back and let it become what it will—with only a slight helping hand. That’s when the true rewards begin.

Richard Liberto is a landscape designer and horticulturist specializing in naturalistic and regional landscape design. libertodesign@comcast.net