In spring, at least for a while, strong sunlight reaches the ground in the shady deciduous woodlands of the Delaware Valley. The frost in the soil melts and warmth reaches plant roots. Sunshine touches stems, tree trunks, and buds, and they start to grow.
Walk through the woods in April and early May, and you will see that countless native flowering plants have sped into bloom before the trees have leafed out fully. Spring is their season to shine.
The floral extravagance appears in waves and layers, with wild cherries, plums, and crabapples blooming up high, rhododendrons and azaleas and other shrubs at eye level, and a gorgeous, amazing carpet of bloodroots, creeping or woodland phlox, Virginia bluebells, trilliums, hepatica, marsh marigold, Jack-in-the-pulpit, ramps, mayapples, bleeding hearts, wild geranium (my favorite), and more, covering the ground.
The beautiful plants are processing the sun, attracting pollinators, and facilitating their floral destiny as creators of seeds for the next generation of plants.
Native plants are tougher than they look. They grow in layers underground as well as above. Ephemeral but perennial flowers including their leaves, bloom and fade before summer, but their spaces are covered with ferns and later-blooming perennials. Their strong, woody roots coexist.
There is a lot of shade in the rich, moist Delaware Valley because large trees thrive here naturally. Trees will eventually seed into any open piece of land where they are not cleared off. Their leaves or needles enrich the soil below them and also shade out competing plants. Woodsy soil types are also affected by the underlying rock and are acidic in most places, but more alkaline where limestone or greenstone (serpentine) rocks predominate.
There are several main types of shade, not just one. In order to recreate the multilayered forest, it helps to understand and manage what you have.
On the darker end is the unchanging shade from walls and dense evergreen trees. This shade is too constant for most wildflowers, but a few, along with ferns and mosses, can manage in such low light. Under mature evergreens you often find an attractive and airy spot under the branches, with a carpet of fine needles all over the ground. To let in more light, lower limbs can be removed on certain large trees, and fences can be changed from a solid to a more open design.
Then there is the seasonal deep shade underneath leafy trees. Many wildflowers such as Virginia bluebells evolved to do their growing in spring before the overhead leafy canopy fills out and blocks all the sun. Native shrubs such as azaleas, rhododendrons, fothergilla, and mountain laurel grow here.
Moderate removal of lower tree branches can help bring in even more light here, stimulating more blooms on the understory azaleas.
There is a brighter partial shade to be found at the edges of woodlands where streams, roads, lawns, or fields have cut through the woods. In these areas, the disturbed ground and brighter light make it easier for invasive plants to take hold. Vining ones are the worst. If these are kept at bay, these brighter spots can become a free-flowering natural environment for you.
It is exciting to add an understory of wildflowers to your shady areas at home, whatever the degree of shade. Work out a plan. The new garden will be more work than it seems and cannot be done all at once. First see what competing and unwanted invasive plants must be removed. Tops on my hit list are thugs like ivy, bittersweet, wild grape, barberry, pachysandra, poison ivy, garlic mustard, goutweed, and wild rose.
Add large amounts of leaf humus, pine needles, and finely ground bark chips to the soil before planting. The sidebar on native plants for shade gives ideas of kinds of flowers to think about. Not everything must flower—foliage looks lovely in the woods.
Once the right balance of plants is achieved, weeds are few for lack of a place to seed in. Until then, the main challenge in natural gardening is keeping weeds out. At Winterthur, ferns are interplanted with the Virginia bluebells, but do not unfurl until after the bluebells have finished blooming. This combination leaves no opening for invasives.
This region is rich in botanical gardens where you can see woodland gardens and learn more about them. Some notable Delaware Valley spots to tour are Mt. Cuba Center, Winterthur, Longwood Gardens, Bowman’s Hill, Swarthmore’s Scott Arboretum, Morris Arboretum, The Brandywine Conservancy, and Jenkins Arboretum. Their example and, in some cases, educational classes and plant sales, can help you bring home our region’s woodland beauty.
Check out these websites:
Ladybird Johnson Wildflower Center
Wildflowers of the United States
uswildflowers.com (select your state)
Mt. Cuba Center
Bowman’s Hill Wildflower Preserve
Pennsylvania Department of Conservation and Nature
(Sanguinaria canadensis) ~
single and double forms, bright white flowers
(Dicentra cucullaria) ~
small white to cream flowers and fernlike foliage
Fire Pink (Silene virginica) ~
bright pink to red flower clusters
(Tiarella cordifolia) ~
filmy clusters of white flowers, mat-forming
(Hepatica nobilis var. obtusa) ~ petite, neat plants with pink, white, or violet flowers
(Spigelia marylandica) ~
red flowers, yellow inside
(Arysaema triphyllum) ~
hooded green striped flower,
(Podophyllum peltatum) ~
white flowers, umbrella-shaped leaves
(Uvularia grandiflora) ~
pendulous yellow flowers
(Trillium grandiflorum, Trillium erectum, Trillium cernuum, Trillium undulatum) ~ usually white, sometimes pink dramatic wildflowers
(Linnaea borealis) ~
(Mertensia virginica) ~
pale blue pendulous flowers in large bunches on tall stems
(Aquilegia canadensis) ~
red and yellow airy flower clusters
(Geranium maculatum) ~
pink to lavender flowers in clusters
(Anemone cinquefolia) ~
Woodland phlox (left)
(Phlox stolonifera) ~
lavender-blue flowers in
Yellow Trout Lily
(Erythronium americanum) ~
small yellow lilies with