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Arnica Root

Arnica montana (AR-nih-kah mon-TAY-nah)

Family: Asteraceae Non-native Herbaceous

Leopard's-bane is a perennial herb in the Asteraceae (daisy) family native to Europe. Its native habitat includes grasslands, shrub lands, and alpine mountain environments. It can also be found in meadows, dry pine forests, open forests, and pastures. It grows .5 to 2 feet tall with basal downy leaves and flowers that occur May to August. The yellow-orange ray flowers surround the yellow disc florets are followed by achenes. The flowers form as a solitary bloom at the top of each stem. In windy locations, they may need to be staked for additional support. Cutting the stem back before the plant flowers will keep the stems short, as well as produce a secondary bloom. Divide during the spring or fall every few years to keep this plant at its best. Their roots can spread, taking over more space than intended. Maintain this plant to avoid invading other portions of your garden. It tolerates most soils if they are lime free, and a well-drained location in full sun to partial shade, but prefers slightly alkaline moist sandy loam. This plant is toxic, however, has been listed as endangered in many locations due to its collection for medicinal uses. It is used in meadows and other naturalized areas, as well as in rock and pollinator gardens. Insects, Diseases, and Other Plant Problems: No serious insect or disease problems. Weedy tendencies.

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 64 attributes.

How it fits the guild

Guild layer 4 - Herbaceous Optimal soil pH Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Often confused with Taraxacum officinale
Fills a similar niche Allium Chrysanthemum x morifolium Euphorbia hypericifolia

Full plant profile

Growing Conditions
Plant type
Herb; Herbaceous Perennial; Poisonous
Life cycle
Perennial
USDA zones
4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Sand
Soil pH
Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage | Moist
Available space
Less than 12 inches; 12 inches-3 feet
NC region
Coastal; Mountains; Piedmont
Growth rate
Medium
Maintenance
High; Medium
Canopy layer
4 - Herbaceous
Form & Appearance
Habit / form
Clumping
Texture
Medium
Foliage
Deciduous
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Opposite; Rosulate
Leaf shape
Lanceolate
Leaf margin
Serrate
Leaf value
Fragrant
Hairs present
Yes
Leaf detail
While basal leaves are clustered, the stem leaves are opposite and simple. The upper side of the leaves are hairy and have longitudinal veins.
Flower color
Gold/Yellow; Orange
Flower value
Showy
Flower form
Head; Solitary
Flower shape
Radial; Tubular
Flower size
1-3 inches
Flower detail
Flowers are yellow-orange rays surrounding yellow disc florets in late spring to early summer.
Bloom time
Summer
Fruit color
Gold/Yellow
Fruit type
Achene
Fruit detail
The fruits are a bristly, hairy yellow pappus, a modified calyx.
Stem detail
The stems are erect hairy and carry a single flower.
Wildlife & Ecology
Native status
Non-native
Origin
Europe
Wildlife value
Bees, flies, moths and butterflies are attracted to the flowers.
Attracts
Bees; Butterflies; Moths
Play value
Attractive Flowers; Attracts Pollinators; Easy to Grow; Fragrance
Food & Medicine
Harvest time
Fall
Fruit type
Achene

Edibility

Not edible, poisonous.

Uses (ethnobotany)

Dried flower heads have been used in herbal medicine for centuries.

Landscape Use
Landscape location
Meadow; Vertical Spaces
Landscape theme
Butterfly Garden; Pollinator Garden; Rock Garden
Design feature
Border
Garden tags
#yellow flowers #poisonous #border planting #rock garden #bedding plants #contact dermatitis #drought intolerant #herbaceous #endangered #herbaceous perennial #fragrant leaves #acidic soils tolerant #self-fertile #frost tolerant #poisonous if ingested #hairy stems #perennial #weedy #poor soil tolerant
Problems & Resistance
Problems
Contact Dermatitis; Poisonous to Humans; Problem for Children; Weedy
Propagation
Seed
Poison severity
High
Poison parts
Flowers; Roots
Poison symptoms
Poisonous through dermatitis and ingestion. Skin irritation upon contact; after ingestion, heart palpitation, vomiting, drowsiness, shortness of breath, and coma in children.
Toxic principle
Helenalin and its esters
Contact dermatitis
Yes
Toxicity summary
High severity poison; parts: Flowers; Roots; contact dermatitis

Planted at Hunnicutt

Nobody’s planted this one yet.