Shade Gardening by Stephen McCarthy

When talking to people about landscaping for wildlife, one of the most common laments we hear is that they have too much shade and "can’t grow anything." While it’s true that having an abundance of shade on your property changes your choices, that doesn’t necessarily mean that it limits them.

Shade Gardening For more nature habitat information Visit these helpful websites: A Plant's Home A Bird's Home A Homesteader's Home

o put a new twist on an old saying, "the light is always better in someone else’s yard." The same basic gardening principles apply to shady spots as to sunny ones, but you have to study your site conditions carefully and choose plants with extra care to be sure you have a good match. There can even be advantages to a less-than-sunny site. Shade plants generally have more chlorophyll to take full advantage of any available light. These species will thrive in shade but may “burn out" in the sun. Often variegated plants, or those with colorful foliage, will appear more brilliant when located out of direct sunlight. Trees will cut heating and cooling costs when properly situated around your home. Today we plant only one tree for every four that are lost, yet trees combat global warming by consuming carbon dioxide and releasing oxygen, so the trees used in shade gardens may become a critical environmental factor in the years ahead. People often use the term “shade" in a very general manner, but in fact there are several kinds of shade. If your garden gets at least two hours of direct sunlight during the day, that is considered “partial shade." When the sun hits the area only in the early morning or late afternoon, it is generally said to have “light shade." “Filtered light" occurs under trees with small leaves, while the ground beneath large-leafed trees is in “dappled light." If the site receives no direct sunlight, but is open to the sky, it is in “bright light," and if it is

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"The garden of the future will be a shade garden, for all kinds of reasons – fiscal, historical, and most of all, environmental." – Ken Druse The Natural Shade Garden

covered completely, perhaps by a deck or next to a north wall in an urban setting, you have “dense shade." Other terms may be used by different resources, but they will represent similar characteristics. Your geographic location will also have some effect, since light is more intense as you get closer to the equator. It is important to study your garden location throughout the day, and during different times of the year, and make notes on what light conditions are present. For instance, you may have “partial shade" in the early spring, before deciduous trees leaf out, and only “dappled light" in the summer. A site near a building may be in “light shade" at certain times of the year, but have “partial shade" when the sun is higher in the sky. Sometimes you can add reflected light by planting near a light-colored wall or fence. If you match your lighting conditions to the plants that you choose, you can enjoy color and variety – even in a garden with limited exposure to sunlight.

This is especially important to consider when you want to create a shade garden by planting trees. The amount of cover will also affect the temperature and amount of moisture in the soil, which again will influence the plants that you choose.

To create a new grove, you may be able to transplant seedling trees from more crowded conditions elsewhere on your property. For fastest results, choose those that grow quickly and have straight trunks, such as ash, tulip tree, and hackberry.

Those trees with leaves that are close together and grow in a single layer towards the outside of the tree crown are called “monolayered." This would include species such as beech, maple, oak, and hickory, and each branch will create a lot of shade.

When possible, avoid trees with shallow root systems, like maple, sweet gum, willow, poplar, and birch. Their surface roots will make planting other things more difficult later on, and they will rob nearby plants of needed moisture.

More sun will reach the ground when the trees are “multilayered," with smaller leaves arranged in layers moving out from the trunk, such as you find with elm, walnut, and hackberry. The shape of the crown, the spacing of the trees, and whether or not they are deciduous, will also affect the type and amount of shade. If there are dead trees in the area, try to leave them in place because they are valuable sources of food and cover for many birds and animals, and they will enrich the soil as they decay.

You can also design a shade garden by planting in the shadow of an existing building, or creating structures such as arbors which can be covered with vines or shadecloth. Since you won’t have tree roots to worry about, amending the soil and planting in such conditions will be easier than in a wooded area.

Shade Structures

Gazebo or Belvedere

Most commonly, shady conditions in a garden are the result of tree cover. Just as there are different kinds of shade to consider, there are also different types of tree canopies, and they affect the amount of light that reaches the ground.

If you have decided to create or manage an existing woodland area, it’s a good idea to remove invasive species before starting to plant. Leave some saplings of the tree species that you like, because they will then be ready to replace the larger trees if they succumb to age or disease.

Lath House

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Pergola or Arbor

Summer/Garden House

Casino or Roman Summer House Ramada

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"Trees provide a sheltering umbrella during hot summer days, and mute harsh summer light to a verdant, luminous quality. They create an incomparable sense of place and enclosure as well as valuable habitat for wildlife." – Brenda Skarphol in Woodland Gardens, Brooklyn Botanic Garden Series

Including small trees and shrubs in your plan will enhance the site as they grow into maturity. Planting in containers which can then be placed under trees or in other shady locations is another way to grow plants which cannot tolerate full sun. Dirt is another factor. Yours will be some combination of soil, silt, sand, and clay, but the proportions are very important when deciding which species of plants are likely to thrive. We tend to think of forests as having rich, loamy soil, but there are also woodlands which are very dry, or so wet that they are waterlogged much of the time. To determine the soil composition in your site, dig down about 8" and put two cups of dirt in a jar. Fill it with water, put a top on it, shake it hard, and then let it sit for 24 hours. The organic material will now be floating on the top, and underneath it will be layers (in this order) of clay, silt, and sand. Usually the ideal woodland soil has a high percentage of organic matter and silt. Raking up the leaves under the trees each fall, as current gardening practices tend to dictate, interferes with the natural recycling process. If you are concerned about the leaves matting down over the winter, shred them and then return them to the garden bed. This is a much safer way to improve the soil under trees than

to till in compost or other amendments. Disturbing the soil or dramatically changing its depth will often harm the roots of mature trees. Returning to the hole that you dug, fill it with water and wait six hours. If the water is still there, you will want to choose plants that thrive in wet conditions. As a rule, the soil under groups of conifers will be dry and lacking in organic matter, because the needles block rainwater from reaching the ground. Similarly, older trees on suburban lots tend to have dry, infertile soil at their base because of their shallow, spreading roots. Rather than trying to drastically change the soil and moisture conditions, which could damage the mature trees that you want to retain, choose plants in smaller containers so they can be fitted into the spaces between shallow roots, add small deciduous trees which will shed their leaves and gradually add organic matter to the soil, and mulch with compost. It’s a good idea to test the pH of your soil. If your site is under conifers and deciduous trees, it will tend to be more acidic. Property near construction sites or limestone rock formations is likely to be alkaline. Most of the woodland plants that you buy at a nursery prefer a more acidic soil, with a pH of 66.5. Azaleas and rhododendrons,

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two of the most popular shrubs for shady areas, like a pH closer to 5.5. There are many inexpensive kits available to test the pH of your soil, and it’s a good idea to check it in several spots if your garden area is large. Although tall trees block a certain amount of rainfall, the water that does reach the plants beneath them tends to stay on the foliage longer than in a sunny environment, and this can promote disease. Some careful, modest pruning of lower limbs or thinning of the branches (not more than 1/3 per year) can increase air circulation, and you shouldn’t place the plants as close together as in a sunny location. It’s a good idea to water plants with soaker hoses or drip irrigation rather than wetting the leaves, and it’s better to water deeply and then allow the soil to dry out somewhat before watering again. This will encourage deeper roots as well as discourage disease. In nature, many plants manage to co-exist in limited space because some have deep roots, others are shallow, and still others use surface rhizomes. By copying that pattern, you can increase the diversity in your own garden. Plants in natural settings also exhibit a variety of growth patterns. Some appear early in the year, before leaves on the trees block the sunlight, and then go dormant. Others are evergreen, allowing them to produce food year-round, taking advantage of whatever light is available. In addition, in nature you will find that plants grow in “layers." There are tall trees, then a shorter understory of smaller trees and

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shrubs, followed by lower-growing perennials, and finally ground covers. If you choose plants that replicate this pattern, you’ll create a garden that looks natural, allows for a greater variety of species, and is the most useful for wildlife. At the same time, strive to include plants with different bloom times, different leaf types and growth habits for cover, some that are evergreen and others that are deciduous, and some that provide food sources for wildlife, including nectar, nuts, and berries. Some fruits are eaten as soon as they ripen, while others become palatable only after a succession of freezing and thawing, making them good late-winter food sources when most other things have disappeared. There are a few general design tips that will help you create a shade garden that is pleasing to the eye. Because shade plants tend to produce flowers that are more subtle in color, you will rely

Vertical Layers of the Forest

more on texture, shape, and subtle color variations to create impact. Strive for differences in leaf characteristics. Combine feathery ferns with plants having wide, large leaves. Look for variegated leaves and light-colored or peeling bark to add interest. Glossy leaves will have more impact than dull ones, and rounded or weeping forms create a greater sense of space. Plants that are columnar in shape are good for accents. Suitable ground covers will fill the visual gap between the early spring perennials and bulbs and later flowers. Choose ground covers which are hardy but not so vigorous that they will choke out neighboring plants. As long as they don’t form dense root mats, spring bloomers will grow right up through them. As with any wildlife habitat landscaping, provide a water source if possible. This may be a bird bath, a shallow container imbedded in the ground, or a more elaborate pond system. In addition to providing needed water for wildlife, it will reflect light and brighten a shady garden.

CANOPY

Other structural elements to consider are dead logs, which will enrich the soil as they decay and provide a growing medium for lichens and fungi; and interesting rocks among which small plants can nestle and tumble.

UNDERSTORY

Leaf Textures

Shade gardens seem to inspire feelings of peace and relaxation, so plan to include a place to sit and enjoy your surroundings.

– Woodland Gardens, Brooklyn Botanic Garden Series

While it is very likely that your garden will ultimately include plants which are not native to your area, awareness will help you make informed decisions and will encourage you to be sure that native plants are also part of your design. Perennial plants will be the mainstay of your shade garden, but you can also add extra color with shade-loving annuals. Garden catalogues, Internet sources, and your local nursery will offer many suggestions, and will give you further information on the amount of shade tolerance and soil requirements for each species.

This article was written by Maryland Master Wildlife Habitat Naturalist Cathy Gilleland. For more information or for the name of a Master Wildlife Habitat Naturalist in your area, please contact: WindStar Wildlife Institute E-mail: wildlife@windstar.org http://www.windstar.org

SHRUB LAYER GROUND LAYER

ROOT ZONE – Woodland Gardens Brooklyn Botanic Garden Series

At last it’s time to choose your plants! There are many books available on shade gardening, a lot of resources on the Internet, and various other sources of information, including your local County Extension Office.

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WindStar Wildlife Institute is a national, non-profit, conservation organization whose mission is to help individuals and families establish or improve the wildlife habitat on their properties.

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PLANTS FOR SHADE GARDENING Bulbs

NOTE:

Camassia Fawn Lily (Erythronium oregonum, E. revolutum, E. tuolumnense) Fritillaria

For these lists, we have concentrated on species which not only thrive in lower-light conditions, but are also native and useful for wildlife.

Groundcovers

There are many others which could not be included because of limited space.

Green-and-Gold (Chrysogonum virginianum) Partridge Berry (Mitchella repens) Creeping Phlox (Phlox stolonifera) Downy Yellow Violet (V. pubescens) Blue Woods Violet (V. sororia) Spring Beauty (Claytonia virginiana) Red Baneberry (Actaea rubra) Wild Ginger (A. arifolium, A. canadense, A. caudatum) Marsh Marigold (Caltha palustris) Crested Iris (I. cristata) Creeping Holly Grape (Mahonia repens) Wild lily-of-the-Valley (Maianthemum canadense) May Apple (Podophyllum peltatum)

The benefits of using native plants are discussed more fully in other WindStar publications, but they include the fact that they are hardier and more disease resistant, they offer less risk of growing invasively, and they have evolved with local wildlife species to best meet those species’ needs for food and cover. In addition, planting native plants is an investment in the future. Many are threatened – and thus the birds, insects, and animals that depend on them are also at risk – by land development, invasive alien plant species, and gardening practices which tend to limit natural genetic diversity.

Ferns(rarely eaten by deer) Maidenhair (Adiantum aleuticum, A. pedatum) Lady Fern (Athyrium filix-femina) Deer Fern (Blechnum spicant) Walking Fern (Camptosorus rhizophyllus) Male Fern (Dryopteris filix-max) Marginal Shield Fern (Dryopteris marginalis) Ostrich Fern (Matteuccia struthiopteris) Sensitive Fern (Onoclea sensibilis) Cinnamon Fern (Osmunda cinnamomea) Interrupted Fern (Osmunda claytoniana) Rock Polypody (Polypodium virginianum) Christmas Fern (Polystichum acrostichoides) Broad Beech Fern (Thelypteris hexagonoptera)

Grasses Sedge (Carex muskingumensis, C. stricta, C. tumulicola, C. plantaginea) Northern Sea Oats (Chasmanthium latifolium) Bottlebrush Grass (Elymus hystrix) Beardless Wild Rye (Elymus tritichoides) Gamma Grass (Xerophyllum tenax) Deer Grass (Muhlenbergia rigens) River Oats (Chasmanthium latifolium)

Vines Allegheny Vine (Adlumia fungosa) Climbing Aster (A. carolinianus) Clematis (native varieties) Trumpet Honeysuckle (Lonicera sempervirens) Virginia Creeper (Parthenocissus quinquefolia)

Shrubs & Small Trees Serviceberry (Amelanchier canadensis) Hornbeam (Carpinus caroliniana) Dogwood (Cornus florida, C. racemosa, C. sericea, C. alternifolia) Viburnum (V. dentatum, V.acerfolium, V. lentago, V. pruifolium) Highbush Cranberry (V. trilobum) Red Chokeberry (Aronia arbutifolia) Summersweet (Clethra alternifolia) Witch Hazel (Hamamelis virginiana) Oakleaf Hydrangea (Hydrangea quercifolia) Carolina Silverbell (Halesia carolina) Winterberry (Ilex verticillata) Mountain Laurel (Kalmia latifolia) Oregon Grape (Mahonia aquifolium) Bayberry (Myrica pensylvanica) Sourwood (Oxydendrum arboreum) Rhododendrons and Azaleas (many native selections) Aromatic Sumac (Rhus canadensis) Fothergilla (F. major) New Jersey Tea (Ceanothus americanus) Virginia Sweetspire (Itea virginica)

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RESOURCES

“Consider that shady spot in your garden as a challenge and an asset, learn the special needs of shade-loving plants, and your former problem spot becomes a cool, attractive, and refreshing haven to enjoy on a summer day."

Books Some of the many books you may find useful are Easy Care Native Plants by Patricia Taylor, Landscaping with Native Trees by Guy Sternberg and Jim Wilson, and Taylor’s Guide to Natural Gardening.

– Shade Gardening, Ortho Books

Internet These are just a few to get you started. You can find many more sites using any search engine. Please note that these sites do not necessarily concentrate on native plants.

Perennials Wild Ageratum (Eupatorium coelestinum) Windflower (Anemone patens) Columbine (Aquilegia caerulea, A. canadensis, A. chrysantha) Black Cohosh (Cimicifuga racemosa) Astilbe (A. biternata) Goatsbeard (Aruncus dioicus) False Goatsbeard (Astilbe biternata) White Wood Aster (Aster divaricatus) Buff Goldenrod (Solidago sphacelata) White Snakeroot (Eupatorium rugosum) Jack-in-the-Pulpit (Arisaema triphyllum) Hepatica (H. acutiloba) Bloodroot (Snaguinaria canadensis) Celandine Poppy (Chelidonium majus) Virginia Bluebells (Mertensia virginica) Foamflower (Tiarella cordifolia) Bleeding Heart (Dicentra eximia) Dutchmen’s Breeches (Dicentra cucullaria) Phlox (P. divericata) Coral Bells (Heuchera sanguinea, H. americana) White Woodland Milkweed (Asclepias exaltata) Turtlehead (Chelone) Twinleaf (Jeffersonia diphylla) Allegheny Monkey Flower (Mimulus ringens) Miterwort (Mitella diphylla) American Jacob’s Ladder (Polemonium reptans) False Solomon’s Seal (Smilacina racemosa) Big Merrybells (Uvularia grandiflora)

“Imagine the possibilities: a new landscape in which biodiverse gardens link up to form a network of corridors that crisscross the continent, connecting nature preserves so that animals can move freely and plant seeds can disperse. Planting these gardens can be our great gift to the planet."

http://www.chicago-botanic.org/PlantFacts.html (good site from the Chicago Botanic Garden)

http://muextension.missouri.edu/xplor/agguides/ hort/g06911.htm (Missouri Dept. of Horticulture; general info and plant lists)

http://www.extension.umn.edu/distribution/ horticulture/DG1428.html (Minnesota Extention Service; general info and plant lists)

http://www.gardenweb.com/forums/woodland/ (forum for woodland and deep shade gardening)

http://www.agctr.lsu.edu/wwwac/parish/ebr/ mgsgar.htm (master gardener site)

http://www.finegardening.com/kg/features/growing/ 16shadeprint.htm (charts of amounts of required sunlight)

http://www.colostate.edu/Depts/CoopExt/4DMG/ Garden/shadegar.htm (Denver Cooperative Extension Service)

http://www.aplantshome.com/store.html/ The definitive website on plants & horticulture (list of plants from A Plant's Home)

http://www.gifted-gardener.com/giftedgardener/ shadegarden.html (Gifted Gardener horticulturalist; general info and plant lists)

s http://www.lsoft.com/scripts/wl.exe.SL1= SHADEGARDENS&H=MAELSTROM.STJOHNS.EDU (a list serve devoted to shade gardening) s

http://www.suite101.com/welcome.cfm/ shade_gardening (a personal web page devoted to shade gardening)

http://www.lanningpages.com/goldenherb/ links1_garden.html (gardening links of all kinds)

– Janet Marinelli, Going Native, Brooklyn Botanic Garden series

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