These plants deter deer and will grow on your septic bed

Canada rye is one of the native plants you can use while gardening on septic beds Photo by Barbara Smits/Shutterstock

On episode 5, season 4 of the Cottage Life Podcast, gardening expert Lorraine Johnson shares the benefits of native plants for your cottage garden. Listen to the show below, and then the rest of the season here.

If you’re gardening with native plants, matched to your cottage conditions, chances are you’ve already overcome the major cultivation challenge: choosing plants that will thrive. That’s half the battle, but even so, there are other problems that arise, unique to the cottage environment. For example, hungry deer might decimate a prized planting; a grove of white pines can try the patience of even the most adept green thumb; invasive non-native species can threaten to take over the garden and, worse, surrounding wild areas; and septic beds require special care in terms of planting. All these gardening challenges require, though, is a little patience and planning.

Planting on septic beds

Although many cottagers plant turf grass over septic beds, this seems like a bit of a lost opportunity to me—after all, that’s a lot of space to have to mow, when the area could be planted in native flowers.

The proviso is “to keep the septic bed clear of trees, shrubs, and plants with deep roots,” says Jacki Kennedy-Ciphery of Water’s Edge Landscaping in Port Carling, Ont. “You need species that won’t interfere with the functioning of the septic system.” Kennedy-Ciphery sees lots of blackberries and raspberries growing over septics in cottage country, and points to these fast-growing, invasive shrubs as particular “no-no’s.” Instead, she suggests wild strawberries, which have shallow roots and will cover the ground quickly, and clover, a hardy non-native that bounces back from foot traffic and improves the soil. “Native grasses are also good,” she adds, “such as Canada wild rye, prairie dropseed, side-oats grama and, especially, little bluestem, which you can seed and then leave alone—you don’t need to mow it unless you want a play area for kids.” 

Rick Wright of Brackenrig Landscaping in Port Carling, Ont., often plants septic fields with a mix of wildflowers and native ferns, such as lady fern and New York fern. “The flowers will naturalize and the ferns don’t have deep roots, so they won’t interfere with the septic system.” He warns, however, that woody shrubs from surrounding natural areas, like viburnum and dogwood, will seed into the septic bed, and “you should cut those down, so the woody brush doesn’t get established.”

As for wildflower species that will thrive over septic beds but not cause problems, Ken Parker of Sweet Grass Gardens in Hagersville, Ont., likes Canada anemone, pussy-toes, New England aster, wild bergamot, pale purple coneflower, black-eyed Susan, and both grey and stiff goldenrod, all of which “have shallow roots and can get the moisture and nutrients they need in the top few inches of the soil. And they cover the ground well.” Wildflower Farm, a native plant nursery and natural landscaping company in Schomberg, Ont., has developed a “Septic Bed Meadow Mix” for seeding directly into sand and gravel backfill over septic systems. The mix includes tough, attractive native species such as wild columbine, sky blue aster, pale purple coneflower, and beardtongue.

For cottagers who are intent on at least a portion of lawn for outdoor activities, it makes sense to use the septic field for this. Wildflower Farm has developed a blend of native and non-native fescue grasses it has specially cultivated to be low maintenance (fescue species are normally fast-growing and require lots of water). Called the Eco-Lawn, it grows only to approximately 23 cm if left unmowed over the summer (but the grass blades are so fine, they fall over to about 10 cm, giving a nice soft carpet). Along with the lawn’s no-mow appeal, another cottage plus is its drought tolerance; once established, it requires no supplementary watering.

A final word of caution, though, when gardening over the septic bed. “Be careful not to cultivate the soil too deeply—about 15–20 cm,” advises Ken Parker, “and always wear a pair of gardening gloves, especially if your system is old and possibly leaking” 

Plants to deter deer

“Nothing is deer-proof,” says Miriam Goldberger of Wildflower Farm, “but you can plant species that are the cuisine of last resort for deer.” Her list of native perennials not particularly palatable to deer includes lavender hyssop, nodding wild onion, butterfly weed, lance-leaved coreopsis, beardtongue, black-eyed Susan, and stiff goldenrod. Native grasses she recommends as being “very low on deer’s list of favourite foods” include side-oats grama, little bluestem and prairie dropseed.

Jacki Kennedy-Ciphery finds that most of the deer damage she sees is to cultivars (plants that have been selected and bred for specific traits) rather than to native plants. She mentions hostas (a non-native) as particularly vulnerable to deer predation, and notes that “one of the problems with deer is that they trample more than they eat, damaging the crowns of plants.” Some people have had luck discouraging deer by placing human hair or dog hair in the garden bed. Kennedy-Ciphery wraps shavings of Irish Spring soap in pieces of old pantyhose or J-cloth and twist-ties them to a garden stake when her flowers are in bloom. “They dislike it as much as I do.” But if all tricks fail in your garden, she suggests: “Be tolerant of imperfection and be prepared to share your flora with the fauna.”

Planting Under Pines

The dry, acidic, shady conditions under pine trees create a daunting challenge for gardeners. Rick Wright offers one solution: “Don’t fight it! Leave the pine needles where they fall—even import more from other areas – and they make a great ground cover.” Another option is to look in the wild to see what native plants grow naturally under pine trees. Plants to try in these tough conditions include beardtongue, ostrich fern, Solomon’s seal, bunchberry, barren strawberry, Canada mayflower, common strawberry, sharp-lobed hepatica, and three-toothed cinquefoil. You’ll need to water transplants well until they’re established and mulch them with—but of course!—pine needles.

Benign non-natives vs. invasive species

“A lot of people just assume that what they see growing in the wild is native, but that’s not true,” says Tim Cantelon, the owner of Sandhill Nursery in Huntsville, Ont. “There are many exotic species that were brought over from Europe or Asia, and they’ve seeded themselves in the wild.” Examples of such non-native wildflowers include Queen Anne’s lace, chicory, periwinkle, and lily of the valley. While many naturalized, non-native species are relatively well behaved and may even make fine garden specimens, some become invasive in the wild, suppressing native plant populations, and hence should not be planted in cottage gardens because they will escape to the wild, via seeds or spreading roots, and take over. 

Invasive non-natives to avoid include false spirea, periwinkle, snow-on-the-mountain, lily of the valley, crown vetch, dame’s rocket, forget-me-not, mint, Japanese bamboo, goutweed, Norway maple, and purple loosestrife. These should not be planted in the cottage garden and they should be weeded out when they show up uninvited. 

Non-native, naturalized species that do not become invasive in the wild and, hence, may be planted without harm in the cottage garden to add colour or fill a hole include shasta daisies, daylilies, and sedum. 

Sourcing native plants

Although it may seem like a convenient cost-saver to harvest native plants from natural areas around your cottage, resist the temptation to dig plants from the wild. If everyone treated natural areas as free nurseries, we’d have no wild left. However, it is fine to collect seeds from these plants, as long as you do so sparingly; the North American Native Plant Society, in its “Ethical Gardener’s Guidelines,” suggests that you “collect no more than 10 percent of a seed crop from the wild. Leave the rest for natural dispersal and as food for dependent organisms.”

Fortunately, as gardeners’ interest in native plants has grown in the last decade, so too has native plant availability at commercial nurseries. As Rick Wright points out, “most garden centres have stock of the common native plants,” such as black-eyed Susans, New England asters, wild bergamot, and wild columbine. For less commonly available native species, such as little bluestem and sky blue aster, you may need to source them at specialty native plant nurseries, but these are great places to visit anyway—the staff tend to be very knowledgeable and passionate about native plants and can offer a wealth of advice. (See Source Guide, p. 152, for specialty nurseries.)

It’s also important to source plants from local nurseries in cottage country. As Jacki Kennedy-Ciphery says, “Plants behave differently here than they do in the city. Plants have to fend for themselves with less consistent moisture, colder temperatures, drying winds off the lake, and sometimes poor soil quality. So my advice is to go to the professional nurseries in the communities where your cottage is, not to the nurseries in the city, because it’s a different climate and the local professionals understand the microclimate.” Wright concurs: “There’s no better source than a local nursery; their plant material has been grown in the area and wintered over in the area, so you know it will have a better chance of surviving and eventually thriving.”  

Local plants, local sources, local knowledge—native plant gardening, in the end, really does come down to learning and honouring the specifics of your cottage landscape and celebrating its uniqueness in the garden.

Plants for your septic bed

  1. Barren strawberry (Waldsteinia fragarioides)
  2. Wild strawberry (Fragaria virginiana)
  3. White clover (Trifolium repens)
  4. Little bluestem (Schizachyrium scoparium)
  5. Prairie dropseed (Sporobolus heterolepis)
  6. Side-oats grama (Bouteloua curtipendula)
  7. Canada wild rye (Elymus canadensis)
  8. Canada anemone (Anemone canadensis)
  9. Plantainleaf pussytoes (Antennaria plantaginifolia)
  10. New England aster (Aster novae-angliae)
  11. Wild bergamot (Monarda fistulosa)
  12. Grey-headed coneflower (Ratibida pinnata)
  13. Black-eyed Susan (Rudbeckia hirta)
  14. Stiff goldenrod (Solidago spp.)
  15. Grey goldenrod (Solidago xxx)
  16. Wild columbine (Aquilegia canadensis)
  17. Sky blue aster (Aster azureus)
  18. Pale purple coneflower (Echinacea pallida)
  19. Beardtongue (Penstemon digitalis)
  20. Lady fern (Athyrium filix-femina)
  21. New York fern (Thelypteris noveburacensis)

Plants to deter deer

  1. Lavender hyssop (Agastache foeniculum)
  2. Nodding onion (Allium cernuum)
  3. Butterfly weed (Asclepias tuberosa)
  4. Lance-leaved coreopsis (Coreopsis lanceolata)
  5. Beardtongue (Penstemon digitalis)
  6. Black-eyed Susan (Rudbeckia hirta)
  7. Stiff goldenrod (Solidago rigida)
  8. Side-oats grama (Bouteloua curtipendula)
  9. Little bluestem (Schizachyrium scoparium)
  10. Prairie dropseed (Sporobolus heterolepis)

Plants for under pines

  1. Beardtongue (Penstemon digitalis)
  2. Solomon’s seal (Polygonatum biflorum)
  3. Bunchberry (Cornus canadensis)
  4. Barren strawberry (Waldsteinia fragarioides)
  5. Common strawberry (Fragaria virginiana)
  6. Canada mayflower (Maianthemum canadense)
  7. Sharp-lobed hepatica (Hepatica acutiloba)
  8. Three-toothed cinquefoil (Potentilla tridentate) 

Further reading

  1. Forest Plants of Central Ontario, by Brenda Chambers, Karen Legasy and Cathy V. Bentley (Lone Pine, 1996)
  2. Forest Plants of Northeastern Ontario, by Karen Legasy ( Lone Pine, 1995)
  3. Ontario Wildflowers, by Linda Kershaw (Edmonton: Lone Pine, 2002)
  4. Shrubs of Ontario, by James H. Soper and Margaret L. Heimburger (Royal Ontario Museum, 1994)
  5. Peterson’s Field Guide to Wildflowers, by Roger Tory Peterson and Margaret McKenny (Houghton Mifflin, 1968)

The last of our four-part series will look at collecting, storing, and planting native seeds from the wild. Lorraine Johnson is the author of The New Ontario Naturalized Garden. Her most recent book is The Gardener’s Manifesto.

This essay appeared in the August 2003 issue of Cottage Life as the third part of a four-part series. You can find the rest here: Part 1: Let native plants guide your gardening, Part 2: Understanding soil and landscape quality when gardening, Part 4: Seed-planting guide for natural gardens.

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