Perennials for Shade in Dry or Moist Areas: A Toronto Master Gardeners Guide

Perennial ferns, pink Astilbe and Hostas, in one of their many foliage variations, combine beautifully in this shade garden. Photo: Helen Battersby

Perennials are hardy ornamental plants that survive in a garden for at least 3 years, and die back to the ground each winter in colder climates. Not all plants with the ability to be perennial are hardy in all areas. This is why planting zones are so important. Knowing your garden zone will allow you to determine which perennials will survive in your area.

Uses

Perennials may be used as ground covers, mixed with annuals, grown in containers, and/or used as accents or specimen plants. On average, perennials flower for 3 or 4 weeks at most, so when planning a perennial garden one should consider flowering time, foliage, plant form and size to ensure colour and interest throughout the gardening season.

Characteristics of Perennials for Shade

Many plants that thrive in shade have developed large leaves and interesting foliage as a way to capture as much sunlight as possible. Hostas are a good example of this. In summer the foliage of shade plants often becomes the focal point of the garden. Use a mixture of perennials with a variety of leaf colours, shapes and textures to create visual and seasonal interest.

Planting Perennials for Shade

Select the appropriate perennial for your garden by determining light conditions, water requirements, climate, and the soil makeup.

Perennials fall into three large groups when it comes to light requirements:

  • Deep shade: refers to the absence of sunlight, even during the daylight periods.
  • Partial Shade: is filtered light found beneath trees with high limbs. Partial shade usually offers some protection from the direct afternoon sun.
  • Full Sun: refers to six to eight hours of direct sun per day.

Exposure to wind is also an important consideration and will vary depending on the site. Protection from the wind should be given to tall perennials.

Cultural Conditions

Proper initial soil preparation is extremely important for perennials since they typically stay in the same location for many years. Add organic matter such as well-rotted manure or compost by topdressing the area to be planted. This improves moisture retention and adds nutrients without disturbing the soil structure.

Amend clay soil by adding 2 inches of coarse sand to improve drainage and aeration. Amend sandy soil by adding 2 to 3 inches of peat moss or organic matter to improve water retention. The added material will be incorporated into the soil by microorganisms already present, and also by you when you dig a hole for your new perennials.

Pests and Diseases

Few major pest and disease problems will arise in perennial gardens if the right plant has been chosen for the right place. This means carefully selecting plants to match existing light conditions, drainage, soil type, etc. Some common pest and disease problems are: powdery mildew, botrytis, root/crown rot, fungal leaf spots, tospoviruses, bacterial blight, and downy mildew.

Monthly inspections for insects and diseases will keep you aware of potential problems. Observe the details of plant appearance and takes notes. Be careful to avoid over or under watering. Good sanitation practices are also important. Remove any diseased or decaying plant material and remove any weeds as they appear.

Due to the new pesticide law, and in the interest of preserving biodiversity, we only recommend organic controls. Spraying water from a hose can knock off most aphids and spider mites. Hand picking for larger insects is also an option. Approved insecticidal soaps may be used for control measures. Insect traps and organic dust barriers can be effective for crawling insects. Natural insect controls include lady bugs and nematodes.

Perennials Tolerant of Dry Shade

Anemone x hybrida (Japanese Anemone)

Aster cordifolius (Heart-Leaved Aster)

Bergenia (Bergenia)

Brunnera macrophylla (False Forget- Me- Not)

Convallaria majalis (Lily-of-the-Valley)

Corydalis lutea (yellow Fumewort)

Dryopteris filix-mas (Male Fern)

Epimedium (Barrenwort)

Erythronium (Fawn-Lily)

Hedera helix (English Ivy)

Hosta (Hosta)

Hystrix patula (Bottlebrush Grass)

Lamium maculatum (Spotted Dead Nettle)

Lysimachia nummularia (Moneywort)

Polygonatum (Solomon’s Seal)

Polystichum acrosticoides (Christmas Fern)

Viola palmata (Early Blue Violet)

Viola pubescens (Downy Yellow Violet)

Waldsteinia (Barren Strawberry)

Perennials for Moist Shade

Adiantum pedatum (Maidenhair Fern)

Arisaema triphyllum (Jack-in-the-Pulpit)

Aruncus dioicus (Sylvan Goatsbeard)

Astilbe (False Spirea)

Chelone (Turtlehead)

Actaea syn Cimicifuga (Bugbane)

Eupatorium (Joe-Pye-Weed)

Filipendula (Meadowsweet)

Epimedium (Barrenwort)

Lobelia cardinalis (Cardinal Flower)

Physostegia (Obedient Plant)

Primula beesiana (Bee’s Primrose)

Tradescantia (Spiderwort)

Trollius (Globeflower)

Viola obliqua (Marsh Blue Violet)

Woodwardia (Chain Fern)

References

Tenenbaum, Frances ed. Taylor’s 50 best Perennials for Shade. New York: Houghton Mifflin Company,1999

The Gardening Encyclopedia. New York: Orbis Publishing Limited, 1985-1992-1995.

The Time-Life Complete Gardener Perennials. Alexandria,Virginia: Time-Life Books, 1995.

Date revised: January 2012

For printable version, click:  Perennials for Shade in Dry or Moist Areas – A Toronto Master Gardeners Guide

Produced by the Toronto Master Gardeners, these Gardening Guides provide introductory information on a variety of gardening topics.

Toronto Master Gardeners are part of a large, international volunteer community, all committed to providing the public with horticultural information, education and inspiration.  Our goal is to help Toronto residents use safe, effective, proven and sustainable horticultural practices to create gardens, landscapes and communities that are both vibrant and healthy.

If you have further gardening questions, reach us at our gardening advice line 416 397 1345 or by posting your question here in the Ask a Master Gardener section.  To book Toronto Master Gardener volunteers for talks, demonstrations, advice clinics, or other services, please contact us at 416 397 1345  or bookamg@torontomastergardeners.ca