Choosing The Right Plants for your LID Feature

Photo Credit: Brendan Gallant, Credit Valley Conservation (https://files.cvc.ca/cvc/uploads/2022/03/com_uo_rain-ready-plant-list_20240125_a.pdf) 

  There are some very important steps when creating an LID feature such as a rain garden or bioswale and plant choice is one of the most important. Choosing the right plants for your feature will ensure that your garden is working at maximum efficiency and also provides you with a very aesthetically pleasing garden to enjoy.

  There are 2 main factors that affect your plant choices for these features, the first being sun exposure. It is recommended that when installing a LID feature like a rain garden, a full sun area is best suited. With full sun, you are able to plant native prairie plants which are known for their deep roots that help loosen the soil which help water infiltrate deeper and with ease. This does not mean that you cannot implement these features in shadier locations, but you will need to consider other plant choices that aren't as common including using shrubs. More to come on plants for shadier sites in a future post.

  The second thing to think about when choosing your plants is knowing what types of plants are best suited for the different areas in your feature. Rain Gardens can easily be split up into 3 zones. The High zone, middle zone, and low zone. Each of these zones in your feature will be exposed to varying amounts of water so it is important to think about what plants would do best suited based on water requirements. 

Read along as we breakdown the different zones and provide examples of some proven powerhouse plants to add to your next project. 

The High Zone

Photo Credit: Brendan Gallant, Credit Valley Conservation (https://files.cvc.ca/cvc/uploads/2022/03/com_uo_rain-ready-plant-list_20240125_a.pdf) 

  The High Zone in a rain garden is considered the out edges of your feature up until the top of the berms (if using in design). In this area, plants are exposed to the least amount of water and in most cases will never receive water introduced to the feature through the inlet unless a large rainfall event occurs. These plants will mostly receive their water from falling rain and being intentionally watered. 

  For this zone, it is recommended to use plants that would be considered drought tolerant. Drought tolerant plants can survive and grow with small amounts of water which is perfect for this area and will reduce overall maintenance. If you choose plants that require a moderate amount of water, even once established, these plants will require consistent watering during the drier season to stay happy. By intentionally designing the High Zone with more drought tolerant plants, you will reduce the amount of maintenance needed and increase the chances of your plants establishing and spreading. 

High Zone Plant Examples:

Flowers

1. Heart-leaved Aster (Symphyotrichum cordifolium)- Drought and salt tolerant, blooms in late season.

2. Prairie Smoke (Geum triforum)- Drought and salt tolerant. Blooms early in the season.

3. Foxglove Beardtongue (Penstemon digitalis)- Drought and salt tolerant. Blooms mid season.

4. Wild Bergamot (Monarda fistulosa)- Drought and salt tolerant. Blooms mid-season. 

5. Black eyed Susan (Rudbeckia hirta)- Drought and salt tolerant. Blooms mid to late season.

6. Dense Blazing Star (Liatris spicata)- Drought tolerant. Blooms late in the season.

7. Giant Blue Hyssop (Agastache foeniculum)- Drought tolerant. Blooms in late season. Aromatic.  

8. Grey-stemmed Goldenrod (Solidago nemoralis)- Drought and salt tolerant. Blooms in late season.

9. Pearly Everlasting (Anaphalis margaritacea)- Drought and salt tolerant. Blooms from mid to late season.

10. Lance-leaf coreopsis (Coreopsis lanceolata)-Drought and salt tolerant. Blooms mid to late season.

11. Wild Strawberries (Fragaria virginiana)- Drought and salt tolerant. Blooms in early season. Good groundcover option.

12. Low Calamint (Clinopodium arkansanum)- Drought tolerant. Blooms mid season. Aromatic. Good groundcover option.

Grasses

13. Little Bluestem (Schizachyrium scoparium)- Drought and salt tolerant. Blooms late season. 

14. Pennsylvania sedge (Carex pensylvanica)- Drought and salt tolerant. Blooms early season. Shade tolerant.

15. Prairie Dropseed (Sporobolus heterolepis)- Drought tolerant. Blooms mid to late season. 

Shrubs

16. Smooth Arrowwood (Viburnum dentatum)- Drought and salt tolerant. Blooms early season.

17. Grey Dogwood (Cornus racemosa)- Drought and salt tolerant. Blooms mid season.

18. Common Juniper (Juniperus communis)- Drought and salt tolerant. Evergreen.

19. Northern Bush Honeysuckle (Diervilla lonicera)- Drought tolerant. Blooms mid season. Shade tolerant.

The Middle Zone

Photo Credit: Brendan Gallant, Credit Valley Conservation (https://files.cvc.ca/cvc/uploads/2022/03/com_uo_rain-ready-plant-list_20240125_a.pdf) 

The Middle Zone in a rain garden is considered to be the outer edge of the bowl to the top of the slope. In this area, plants will receive water during rain events, but soil will dry at a much faster rate than in the bowl of the feature. In the height of summer, these plants may experience drought. Therefore, choosing plants that have a wider range of conditions they can tolerate would be the best option for this zone. 

  Another thing to consider when choosing plants for this area is stabilizing the slope. To prevent erosion in your feature, using plants that grow quickly and establish deep roots are a great option to plant on the slope of your feature. Native prairie grasses are especially effective in stabilizing slopes and should be considered when deciding on plants for your feature. Check out the examples below of plants that are a good choice for the middle zone of your feature.

Middle Zone Plant Examples:

Flowers

1. Golden Alexanders (Zizia aurea)- Drought and salt tolerant. Blooms early season. Black Swallowtail host plant.

2. Canada Anemone (Anemonastrum canadense)- Salt tolerant. Blooms early season. Fast grower. 

3. New England Aster (Symphyotrichum novae-angliae)- Drought and salt tolerant. Blooms late season. Fast grower.

4. Prairie Smoke (Geum triforum)- Drought and salt tolerant. Blooms early season. 

5. Foxglove Beardtongue (Penstemon digitalis)- Drought and salt tolerant. Blooms mid season. Fast grower. Easy to propagate by seed.

6. Black eyed Susan (Rudbeckia hirta)- Drought and salt tolerant. Blooms mid season. Fast grower. Easy to propagate by seed.

7. Wild Columbine (Aquilegia canadensis)- Drought and salt tolerant. Blooms early season. Great pollinator plant.

8. Zigzag Goldenrod (Solidago fexicaulis)- Drought and salt tolerant. Blooms late season. Fast grower. Good shade option.

9. Blue Vervain (Verbena hastata)- Salt tolerant. Blooms mid season. Spreads easily.

10. Wild Strawberries (Fragaria virginiana)- Drought and salt tolerant. Blooms in early season. Good groundcover option. 

11. Great Blue Lobelia (Lobelia siphilitica)- Blooms in late season. Thrives in moist conditions. Short lived but fast grower.

Grasses

12. Big Bluestem (Andropogon gerardi)- Drought and salt tolerant. Blooms late season. 

13. Tufted Hairgrass (Deschampsia cespitosa)- Drought and salt tolerant. Blooms mid season. Shade tolerant.

14. Switchgrass (Panicum virgatum)- Drought and salt tolerant.  Blooms in late season. Can be used in any zone. 

15. Yellow Indiangrass (Sorghastrum nutans)- Drought and salt tolerant. Blooms mid to late season. 

16. Path Rush (Juncus tenuis)- Drought and salt tolerant. Blooms early season. 

17. Fox Sedge (Carex vulpinoidea)- Salt tolerant. Blooms in early season. Thrives in moist conditions. Fast spreading groundcover.

Shrubs

18. Oakleaf Hydrangea (Hydrangea quercifolia)- Blooms mid season. Shade tolerant.

19. Alternate-leaved Dogwood (Cornus alternifolia)- Drought tolerant. Blooms mid season. Large shrub. Shade tolerant.

20. Red Osier Dogwood (Cornus sericea)- Drought tolerant. Blooms mid season. Fast grower.Winter interest.

21. Nannyberry (Viburnum lentago)- Drought tolerant. Blooms early season. Large Shrub.

22. Eastern Ninebark (Physocarpus opulifolius)- Drought and salt tolerant. Blooms early season. Great shrub for any zone.

23. Purple Flowering Raspberry (Rubus odoratus)- Drought and salt tolerant. Blooms mid season. Fast grower. Shade tolerant.

24. Witch-hazel (Hamamelis virginiana)- Drought tolerant. Blooms late season. Shade tolerant. Large shrub

The Low Zone

Photo Credit: Brendan Gallant, Credit Valley Conservation (https://files.cvc.ca/cvc/uploads/2022/03/com_uo_rain-ready-plant-list_20240125_a.pdf) 

  The Low Zone is the most important part of your feature. This is the area in the feature where water will gather and infiltrate. By having plants that thrive in wet soil conditions, the plants will grow and create gaps in the soil as they spread their roots. This will increase the rate at which water will infiltrate the soil. Using native plants in this area can be particularly useful because there are native plants that are adapted to a large range of soil conditions. Take note of the hardy plants that are drought tolerant but also do well in moist conditions.

  The greater the amount of plant mass in this area, the greater amount of water is absorbed by plant material alone resulting in a faster draining and overall more effective LID feature for storm management. Having plants that soak up a large amount of water entering the system, it is almost certain you will never see water flowing out of the system and that's the ultimate goal!  Take a look at the examples below of some moisture loving native plants. 

Low Zone Plant Examples:

Flowers

1. Flat-top Aster (Doellingeria umbellata)- Drought and salt tolerant. Blooms in late season. Northern crescent butterfly host plant.

2. Blue Flag Iris (Iris versicolor)- Salt tolerant. Blooms in early season. Thrives in moist conditions. 

3. Strict Blue-eyed-grass (Sisyrinchium montanum)- Drought and salt tolerant. Blooms in early season. Easy to propagate by seed.

4. Cardinal Flower (Lobelia cardinalis)- Blooms in late season. Thrives in moist conditions. Attracts hummingbirds.

5. Roundleaf Goldenrod (Solidago patula)- Blooms in late season. Thrives in moist conditions. 

6.Spotted Joe-Pye Weed (Eutrochium maculatum)- Drought and salt tolerant.Thrives in moist conditions. Blooms in late season.

7. Great Blue Lobelia (Lobelia siphilitica)- Blooms in late season. Thrives in moist conditions. Short lived but fast grower.

8. Swamp Milkweed (Asclepias incarnata)- Drought and salt tolerant. Blooms in mid season. Thrives in moist conditions. Monarch butterfly host. 

9. Square-stemmed Monkeyflower (Mimulus ringens)- Blooms in mid season. Thrives in moist conditions. 

10. Common Silverweed (Potentilla anserina)- Drought and salt tolerant. Blooms in mid season. Thrives in moist conditions. Fast spreading groundcover.

11. White Turtlehead (Chelone glabra)- Blooms in late season. Thrives in moist conditions. Shade tolerant.

Ferns

12. Cinnamon Fern (Osmundastrum cinnamomeum)- Thrive in moist conditions. Shade tolerant.

13. Marginal Wood Fern (Dryopteris marginalis)- Thrives in moist conditions. Semi-evergreen. Shade tolerant.

14. Ostrich Fern (Matteuccia struthiopteris)- Drought tolerant. Thrive in moisture. Fast grower. Shade tolerant.

Grasses

15. Bluejoint Reedgrass (Calamagrostis canadensis)- Salt tolerant. Blooms in early season. 

16. Soft Rush (Juncus efusus)- Salt tolerant. Blooms in early season. Thrives in wet conditions. Fast grower.

17. Bearded Sedge (Carex comosa)- Blooms early to mid season.

18. Fox Sedge (Carex vulpinoidea)- Salt tolerant. Blooms in early season. Thrives in moist conditions. Fast spreading groundcover.

19. Fringed Sedge (Carex crinita)- Blooms in early season. Thrives in moist conditions. 

20. Virginia Wildrye (Elymus virginicus)- Drought and salt tolerant. Blooms mid to late season. Thrives in moist conditions. 

Shrubs

21. Buttonbush (Cephalanthus occidentalis)- Drought and salt tolerant. Blooms in mid season. Thrives in moist conditions. Medium to large shrub.

22. Common Elderberry (Sambucus canadensis)- Blooms in mid season. Thrives in moist conditions. Large Shrub. Edible fruit. 

23. White Meadowsweet (Spiraea alba)- Drought tolerant. Blooms in mid season. Thrives in moist soil. Spring azure butterfly host. 

24. Winterberry (ilex verticillata)- Blooms in early season. Thrives in moist conditions. Need male and female plants to produce berries. Shade tolerant. Winter interest.

25. Northern Spicebush (Lindera benzoin)- Drought and salt tolerant. Blooms in early season. Tolerates moist soil. Aromatic. Needs male and female plants to bear fruits. Shade tolerant.