castor aralia
(Kalopanax septemlobus)
This species is Introduced in the United States
ORIGIN: Asia
GROWTH TRAITS: Deciduous tree typically growing 40-60' (12.2-18.3 m) tall, though individuals can grow much taller in their native range. Trees grow from a shallow, fleshy root system that may occasionally send up root sprouts. There is often one main trunk that branches to form an upright, oval canopy. Young bark is armed with long, thick spines; mature bark is generally spine-less, grayish-brown, and deeply furrowed. Leaves are 7-12" (18-30 cm) across, alternate, and attached to the branch with long petioles. Leaves, typically with 5-7 lobes, are shaped like the palm of a hand. Lobes may be shallow, or deeply divided nearly to the leaf base. Lobe margins are finely toothed. Leaves are dark glossy green initially, turning dull yellow to red in fall, but are not particularly showy. Flowers appear profusely in large clusters of umbels at stem branches in late summer. Each flower is tiny with 4-5 creamy white petals. The tiny, berry-like fruits occur in ball-like clusters and are black at maturity. Trees generally live over 40 years.
REPRODUCTION: Spreads by seed and sprouting from the root system. Though the seeds are considered short-lived, some remain viable for at least two years.
HABITAT: Tolerates partial shade to full sun and grows best in deep, moist, fertile, well-drained soil. Castor aralia prefers cool, moist climates and is very cold tolerant. It can be found escaping landscaping and invading field and forest margins.
LOOK-ALIKES: The combination of tree habit, grayish furrowed bark, lobed leaves resembling the palm of a hand, and ball-like fruiting structures help differentiate castor aralia from most potential look-alikes. The native sweetgum (Liquidambar styraciflua) has similar bark, toothed leaves with 5 palm-like lobes, and a ball-like fruiting structure. It differs from castor aralia by having thorn-less young bark, dense clusters of very non-showy green flowers, and fruits that become woody at maturity rather than consisting of numerous black, berry-like fruits. The native devil's walking stick (Aralia spinosa) resembles young castor aralia with its somewhat similar flowers and fruit and its stems armed with long spines. Devil's walking stick grows smaller and its leaves are large and compound with numerous ovate leaflets.
CITATIONS:
Rawlins, K.A., R.L. Winston, C.T. Bargeron, D.J. Moorhead, and R. Carroll. 2018. New Invaders of the Northeast and Northcentral United States. USDA Forest Service, Forest Health Assessment and Applied Sciences Team, Morgantown, West Virginia. FHTET-2017-04. Retrieved from https://bugwoodcloud.org/resource/pdf/FHTET-2017-04_New%20Invaders_NE.pdf
GROWTH TRAITS: Deciduous tree typically growing 40-60' (12.2-18.3 m) tall, though individuals can grow much taller in their native range. Trees grow from a shallow, fleshy root system that may occasionally send up root sprouts. There is often one main trunk that branches to form an upright, oval canopy. Young bark is armed with long, thick spines; mature bark is generally spine-less, grayish-brown, and deeply furrowed. Leaves are 7-12" (18-30 cm) across, alternate, and attached to the branch with long petioles. Leaves, typically with 5-7 lobes, are shaped like the palm of a hand. Lobes may be shallow, or deeply divided nearly to the leaf base. Lobe margins are finely toothed. Leaves are dark glossy green initially, turning dull yellow to red in fall, but are not particularly showy. Flowers appear profusely in large clusters of umbels at stem branches in late summer. Each flower is tiny with 4-5 creamy white petals. The tiny, berry-like fruits occur in ball-like clusters and are black at maturity. Trees generally live over 40 years.
REPRODUCTION: Spreads by seed and sprouting from the root system. Though the seeds are considered short-lived, some remain viable for at least two years.
HABITAT: Tolerates partial shade to full sun and grows best in deep, moist, fertile, well-drained soil. Castor aralia prefers cool, moist climates and is very cold tolerant. It can be found escaping landscaping and invading field and forest margins.
LOOK-ALIKES: The combination of tree habit, grayish furrowed bark, lobed leaves resembling the palm of a hand, and ball-like fruiting structures help differentiate castor aralia from most potential look-alikes. The native sweetgum (Liquidambar styraciflua) has similar bark, toothed leaves with 5 palm-like lobes, and a ball-like fruiting structure. It differs from castor aralia by having thorn-less young bark, dense clusters of very non-showy green flowers, and fruits that become woody at maturity rather than consisting of numerous black, berry-like fruits. The native devil's walking stick (Aralia spinosa) resembles young castor aralia with its somewhat similar flowers and fruit and its stems armed with long spines. Devil's walking stick grows smaller and its leaves are large and compound with numerous ovate leaflets.
CITATIONS:
Rawlins, K.A., R.L. Winston, C.T. Bargeron, D.J. Moorhead, and R. Carroll. 2018. New Invaders of the Northeast and Northcentral United States. USDA Forest Service, Forest Health Assessment and Applied Sciences Team, Morgantown, West Virginia. FHTET-2017-04. Retrieved from https://bugwoodcloud.org/resource/pdf/FHTET-2017-04_New%20Invaders_NE.pdf
Selected Images
Maps
EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Lists - This map identifies those states that have this species on their invasive species list or law.
Invasive Listing Sources
- City of Ann Arbor Michigan Parks and Recreation
- Jil Swearingen, personal communication, 2009-2017
- Maryland Invasive Species Council - Invasive Species of Concern in Maryland
- National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
- New Invaders of the Northeast and Northcentral
- New Jersey Invasive Species Strike Team 2017 Invasive Species List
- Non-Native Invasive Plants of Arlington County, Virginia
- Non-Native Invasive Plants of the City of Alexandria, Virginia
- Plant Invaders of Mid-Atlantic Natural Areas
Taxonomic Rank
| Domain: Eukarya |
| Kingdom: Plantae |
| Phylum: Magnoliophyta |
| Class: Magnoliopsida |
| Superorder: Asteranae |
| Order: Apiales |
| Family: Araliaceae |
| Genus: Kalopanax |
| Kalopanax septemlobus |
References
Common Name Reference: USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.
Scientific Name Reference: USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.