1. Canadian Wild Ginger
Name: Asarum canadense
USDA hardiness zones: 2 to 8
Size: 6 to 8 inches tall, spreading indefinitely
Conditions: Partial to full shade; moist, well-drained soil
Although big heart-shaped leaves are the main attraction with this North American native, its curious bell-shaped flowers are another bonus. A moderate spreader, Canadian wild ginger forms a dense mat of fresh foliage from early spring through summer. While many shallow-rooted ground covers collapsed during the 2012 drought, this one made it through without a whimper. Better yet, deer don’t touch it, and diseases don’t seem to bother it.
2. Kyushu Meadow Rue
Name: Thalictrum kiusianum
Zones: 4 to 8
Size: 4 to 6 inches tall and 8 to 12 inches wide
Conditions: Partial shade; moisture-retentive soil
Just for fun, I keep a mental tally of perennials noted for their extended bloom time; for years, Kyushu meadow rue has topped the list. From late spring though late fall, not a day goes by that this spreader isn’t awash in a froth of light lavender starbursts. Kyushu meadow rue also fairs well unsheltered through winter; withstands drought, even though it prefers an evenly moist soil; and isn’t deterred by annual division, so I can share this one with friends.
3. Pennsylvania Sedge
Name: Carex pensylvanica
Zones: 3 to 8
Size: 8 to 10 inches tall and 12 to 18 inches wide
Conditions: Partial to full shade; average soil
I would grow this sedge for its graceful cascading habit alone, but the fact that it performs admirably in light to dense shade with scant moisture makes Pennsylvania sedge all the more endearing. Its light green blades are evergreen, forming a splendid foil for spring ephemerals. This North American native spreads gently by shallow rhizomes to form solid colonies and can take light foot traffic without flinching. Though delicate in appearance, this sedge is tough in demeanor.
4. ‘Waterperry Blue’ Speedwell
Name: Veronica ‘Waterperry Blue’
Zones: 4 to 8
Size: 3 to 5 inches tall and up to 18 inches wide
Conditions: Full sun to partial shade; moist, well-drained soil
Many of the upright veronicas resent our hot, muggy summers, becoming mildew magnets and losing their foliage prematurely. ‘Waterperry Blue’ speedwell puts all those varieties to shame. In our gardens, it’s been a perfect ground cover in all regards, letting us literary walk all over it without a single complaint. In cool weather, its green foliage has accents of bronze, and in spring, blue flowers dot the plant and often reappear later in the season.
Steve Kelley is the owner of Kelley & Kelley Nursery in Long Lake, Minnesota.
Photos: #1 and #3, Michelle Gervais; #2, Bill Johnson; #4, Doreen Wynja