HARDINESS: Zones 2 to 8
PREFERRED SOIL pH: Slightly acidic to neutral
PREFERRED SOIL TYPE: Moist, fertile
PREFERRED LIGHT: Partial to full shade
ATTRIBUTES: Handsome mat-forming plants that spread slowly; tor groundcover, beds
SEASON OF INTEREST: Spring through fall
FAVORITES: A. canadense as woodland groundcover; A. europaeum as specimen
QUIRKS: Drought can cause plants to become temporarily dormant
GOOD NEIGHBORS: Cohosh, epimedium, astilbe, hosta, Solomon's seal, trillium, ferns, trees
WHERE IT GROWS BEST: Partial to full shade in moist soil enriched with humus
POTENTIAL PROBLEMS: Slugs and snails
RENEWING PLANTS: Lives many years; top-dress with 1 in (2.5 cm) of compost in the fall
CRITTER RESISTANCE: Good
DIMENSIONS: 5 in (12.7 cm) tall, spreads to broad mats several feet wide
Asarum in the Landscape
Low-maintenance and also low to the ground, asarum is made for the shade. Any place protected from sun will suit this cold-tolerant perennial, which is often called wild ginger. When crushed, the leaves will release the scent of ginger, although they are not considered edible. The plant is so named because its root was once used as a substitute for that exotic spice.
If you need a groundcover plant that's always trim, tidy, and impeccably well-groomed, look no further than Asarum conadense, a native of the North American woodlands. Grown for its 5 in (12.7 cm) tall, downy green, heart-shaped leaves, this species forms a carpet that bears up well when summer weather becomes torridly hot. Its European counterpart, A. europaeum, is similar in shape and size, but its leaves are brighter green with a glossy, waxy shine and subtle veining. It is somewhat less tolerant of heat and drought than its native cousin but remains reliably evergreen through cold winters.
Both wild gingers bloom in early spring as the leaves unfold, but the flowers are easy to miss. Appearing close to the ground, the small, brownish purple, urn-shaped flowers are inconspicuous except for their gently refreshing scent. You'll have to lift the leaves to see, and smell, them.
Care-Free Plants for Shade
Asarums are tough and care-free, and although they spread over time, they are not invasive. New foliage sprouts from wiry underground stems called rhizomes. Wild gingers thrive in shade even where the soil is not deep or rich. They prosper under trees and shrubs, on die northern side of buildings or walls, and in other hard-to-plant spots where sun seldom shines.
Ideal landscape partners for these rich, glossy leaved groundcovers include other Light-shunning perennials, such as epimedium, hosta, Solomon's seal, and trillium, as well as trees and shrubs of all sorts. Wild ginger's broad, smooth leaves are particularly attractive when they are played against the feathery foliage of ferns, astilbe, and meadow rue.
Planting and Caring For Asarum
Buy potted nursery-grown plants of wild ginger in early spring. Dig a 2 in (5.1 cm) deep layer of compost into a shady site and set the plants in at the same depth they grew in their containers, spacing them 6 in (15.2 cm) apart for good ground coverage in time. Growth will be slow for the first year, or maybe two, but eventually asarum forms handsome mats that creep outward while staying low. It looks better and better each season and lasts for many years.
To encourage strong spring growth, spread 1 in (2.5 cm) of compost over the bed every fall. If any of the evergreen leaves show brown edges or other damage from the winter, simply clip back the stem to ground level, and the plant will quickly send up fresh new foliage.
Like many other woodland perennials, asarums defend themselves during drought by going dormant. To keep the plants in leaf through dry spells, water weekly and mulch with a 2 in (5 cm) thick layer of fine bark chips or compost to safeguard soil moisture. At the same time, beware of slugs and snails, which can make a home in damp mulch. Handpick them in the evening, set out saucers of stale beer to trap them, or deter them with a barrier of coarse sand or crushed eggshells around plants.
Increasing the Bounty
Wild ginger grows slowly and rarely needs dividing, but you can dig out rooted sections of the plant about 4 in (10 cm) in diameter and transplant them to a new place in early spring if you want to introduce it to a new area. Fill the hole left behind with loamy soil, and neighboring asarum plants will soon fill the gap.