Asarum
( ah - SAIR - um )
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At-A-Glance InformationCommonly known as Little Jug or Wild Ginger, this genus of perennials includes species which need partial to full shade and regular to ample amounts of water to perform well in the garden. They make great groundcovers for shady garden beds, their foliage contrasting well with other shade-loving plants like ferns. These plants produce small brown to purple-red flowers and roots and leaves have a spicy scent to them. Use Wild Ginger to fill in bare spaces in woodland or shade gardens, in mixed beds or borders, or in containers. Take care when planting these flowers in the landscape, as plant parts are toxic to humans and pets if ingested.
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Asarum Species and Varietals
The genus Asarum is a member of the plant family Aristolochiaceae and includes just under 65 species. The best growing zones for Asarum depend on the species; for more information, read the descriptions below. To find your zone, click here: Zone Map.
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Asarum arifolia (Hexastylis arifolia) (Little Brown Jug, Arrowleaf Heartleaf, Heartleaf Ginger) This wildflower species is found in the southeastern United States, and is considered to be a threatened species in Florida. It grows well in USDA hardiness zones 5a-9b. This evergreen plant has no above-ground stems and spreads via underground rhizomes. Leaves are green and heart-shaped. Flowers form one at a time at the end of creeping rhizomes. Individual plants reach between 6 and 12 inches tall at maturity. |
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Asarum asperum (Heterotropa aspera) (Rough Japanese Wild Ginger, Japanese Wild Ginger) This species is endemic to Japan, and produces thick evergreen leaves and ground-level maroon flowers in April. These plants are at home on woodland forest floors, and commonly grow beside Ainsliaea cordifolia, to which they bear a foliar resemblance. Leaves vary in appearance; cultivar 'Silver Streak' has foliage with a wide central stripe of silver. To 3 feet tall at maturity. Best in USDA zones 6a-9b. |
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Asarum canadense (Canada Wild Ginger, Canadian Snakeroot, Broad-Leaved Asarabacca) This species is native to eastern North America, and is considered a threatened species in Maine. It grows well in USDA hardiness zones 3-7. Iridescent leaves are green and velvety, and flowers are tan to purplish. Plants were traditionally used by Native American populations as a culinary seasoning and to treat a number of physical ailments. Individual plants reach up to 6-12 inches tall at maturity. |
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Asarum caudatum (British Columbia Wild Ginger, Long-Tailed Wild Ginger) Grows best in USDA hardiness zones 7-9 or Sunset growing zones 4-6 and 14-24. This native to the West Coast is considered an evergreen where winters are mild. Leaves are dark green and heart-shaped; this species is great as a groundcover and needs little water once established. If planted in the sun, needs more water to compensate. Leaves will emit a Ginger smell when rubbed. |
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Asarum europaeum (Asarabacca, European Wild Ginger, Hazelwort, Wild Spikenard, Foal's Foot) This creeping evergreen perennial produces glossy green leaves and small purple flowers bloom in late winter and spring. Roots smell of Ginger. This species is native to woodland areas in Europe and grows well in USDA hardiness zones 4-8. Individual plants reach between 4 and 8 inches tall. |
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Asarum hartwegii (Hartweg's Wild Ginger) This species is endemic to California, and has a ginger-scented rhizome root. Leaves are veined with cream to white, and flowers have brown to maroon sepals. Fruits that follow blooms are fleshy capsules containing many seeds. Individual plants reach up to 3 inches tall and 10 inches wide at maturity, and spreads by slowly creeping roots to create a lush natural carpet. Best in USDA zones 6a-10b. |
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Asarum lemmonii (Lemmon's Wild Ginger) This species is endemic to California, and has a spreading habit, forming dense, green, ground-hugging mats of foliage. Flowers have sepals that are red on the exterior and white on the interior. These flowering plants are at home in the high Sierras. |
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Asarum marmoratum (Marbled Wild Ginger) This species is native to California and Oregon in the Klamath and Cascade mountain ranges. Leaves are hairy and green, and flowers are enclosed within sepals that are dark green-brown on the outside and dark red inside. It is considered an endangered species in Oregon. Best in USDA zones 7-9. |
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Asarum maximum (Panda Face Ginger, Green Panda) This interesting species is native to China, and has flowers that smell distinctly of mushrooms. Sepals are white and dark red to black. At maturity, plants reach up to a few inches tall, spreading to a 20 inches wide. Eventually, it forms larger mats of foliage through creeping rootstock. These plants do well in USDA hardiness zones 7-9. Cultivar 'Ling Ling' has dark green leaves with lighter patterning. |
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Asarum minus (Little Heartleaf, Little Brown Jug, Wild Ginger) This low-growing, stemless perennial plant is native to Virginia, North Carolina, and South Carolina and grows well in USDA hardiness zones 5a-9b. It produces flowers protected by white to cream-mottled red sepals that are usually hidden underneath leaf litter in their native habitat. The species was first described by William Ashe in 1897. |
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Asarum splendens (Asarum chingchengense) (Chinese Wild Ginger, Splendid Wild Ginger) This native of China has dark green leaves that are heavily marked with silver. Grows vigorously in rich, loose soil and can form huge colonies of plants if left unchecked. Grows best in USDA hardiness zones 5-9 and Sunset growing zones 3-6 and 15-17. Individual plants reach up to between 5 and 8 inches tall when mature, and have a spread of 10-16 inches. |
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Caring for asarum
Take care when planting these flowers in the landscape, as plant parts are toxic to humans and pets if ingested. These plants can grow in average soil, but prefer to have their roots in rich soil. They can be started from plant divisions or nursery specimens planted about a foot apart for best coverage. They do well in shade, and form thick mats that make ideal groundcovers. Wherever they are planted, make sure they have adequate space to grow, as they will expand and form colonies over time. Ensure that soil is well-draining and has a pH of between 5.5 and 6.8 (slightly acidic to neutral). If local soils are compacted, do not drain well, or are particularly poor in nutrients, make sure to amend the planting area with plenty of organic matter or compost before installing. Apply a thick layer of mulch around the base of the plant after installation, ensuring that mulch stays at least a few inches away from the stems. This will increase soil moisture retention, suppress weed growth, and maintain a constant soil temperature.
Water new plants regularly as they establish a strong root system in their new environment. Mature plants should be given water any time the top inch or two of soil feels dry to the touch. In climates with no frost, rhizomes can be left in the ground over the winter months. Mulching over the tops of plants during the coldest months of the year can help them to survive over winter, as well. In areas with hard freezes, grow these plants in containers and move them indoors or to a more protected location over wintertime. Pruning is relatively straightforward for these plants; after they are done flowering and fruiting, cut back the flowering stem to the base of the plant. Any remaining foliage can be cut back in this way as well. New foliage and flowering stems will form and bloom in the next growing season. These flowers can be divided every few years if they seem to be fading; for instructions on how to successfully divide Asarum plants, see the Propagation section below. These flowers are long-lived, slowly spreading to form swathes of foliage and flowers. Some species have the potential to persist for centuries in the landscape.
Growing Asarum in Containers
Asarum plants are typically grown in the ground, but can also be grown in containers. This cultivation allows for the plants to be moved to a sheltered location during the winter months in zones cooler than their preferred growing climates. Choose a container with adequate drainage holes on the bottom that allow for excess water to flow away. Fill with a well-draining soil substrate that has been amended with organic material and perlite. Top substrate with a layer of mulch, ensuring that it stays at least a few inches away from the stems. This will increase soil moisture retention, suppress weed growth, and maintain a constant soil temperature. Water regularly; Asarum plants grown in containers will need more frequent irrigation than their in-ground counterparts. These flowers can be divided every few years if they seem to be fading; for instructions on how to successfully divide Asarum plants, see the Propagation section below.
Water new plants regularly as they establish a strong root system in their new environment. Mature plants should be given water any time the top inch or two of soil feels dry to the touch. In climates with no frost, rhizomes can be left in the ground over the winter months. Mulching over the tops of plants during the coldest months of the year can help them to survive over winter, as well. In areas with hard freezes, grow these plants in containers and move them indoors or to a more protected location over wintertime. Pruning is relatively straightforward for these plants; after they are done flowering and fruiting, cut back the flowering stem to the base of the plant. Any remaining foliage can be cut back in this way as well. New foliage and flowering stems will form and bloom in the next growing season. These flowers can be divided every few years if they seem to be fading; for instructions on how to successfully divide Asarum plants, see the Propagation section below. These flowers are long-lived, slowly spreading to form swathes of foliage and flowers. Some species have the potential to persist for centuries in the landscape.
Growing Asarum in Containers
Asarum plants are typically grown in the ground, but can also be grown in containers. This cultivation allows for the plants to be moved to a sheltered location during the winter months in zones cooler than their preferred growing climates. Choose a container with adequate drainage holes on the bottom that allow for excess water to flow away. Fill with a well-draining soil substrate that has been amended with organic material and perlite. Top substrate with a layer of mulch, ensuring that it stays at least a few inches away from the stems. This will increase soil moisture retention, suppress weed growth, and maintain a constant soil temperature. Water regularly; Asarum plants grown in containers will need more frequent irrigation than their in-ground counterparts. These flowers can be divided every few years if they seem to be fading; for instructions on how to successfully divide Asarum plants, see the Propagation section below.
Propagation
The best way to propagate these plants is through division of existing rhizome roots of larger plants. If you will be growing your Asarum in a container, this process will need to be completed every few years to make sure there is enough space for healthy root growth. To propagate your Asarum by division, follow the instructions below:
Propagating Asarum by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring. To propagate by division, follow these steps:
Propagating Asarum by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring. To propagate by division, follow these steps:
- Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the rhizome roots. Once you have worked it up out of the ground, lay it out.
- Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section with viable growing points.
- Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divided roots about an inch under the soil surface and water thoroughly. If any part of the rhizome root seems like it is already growing, make sure to place that end of the root towards the soil surface.
- Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout the following springtime.
Problems and Pests
Asarum plants are generally resistant to pests and diseases, though they can have issues with the following from time to time:
- Slugs and Snails
- Leaf Spot
- Rhizome Rot
- Leaf Gall
- Necrotic Spot Virus
Gallery
These plants form great groundcovers for shady to partially shady areas of the landscape.
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Asarum are low-growers, and ideal for woodland landscaping.
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Along this garden pathway, Hosta and low grasses compliment the Asarum grown between stepping stones.
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Videos
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All about wild gingers.
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Learn about this cultivar of Asarum.
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Take a walk through the woods with Mountain Gardens.
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These are great groundcovers for shaded areas.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 172, Asarum
