Perennials

Achlys triphylla

vanilla-leaf

Berberidaceae

Pacific Northwest — BC south to northern California, east to Idaho and Montana; moist conifer forest understory

At a Glance

TypePerennial
HabitSpreading
FoliageDeciduous
Height6-12 inches (15-30 cm) foliage; 8-16 inches (20-40 cm) in bloom
Width12-24 inches (30-60 cm) per plant; spreads indefinitely by rhizome

Growing Zones

USDA Hardiness Zones

5 - 9
Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Attracts Pollinators
Deer Resistant
Fragrant (strong)
Native to North America
Maintenancevery low

Overview

A low-growing, rhizomatous herbaceous perennial in the family Berberidaceae, native to moist conifer forest understories of the Pacific Northwest from British Columbia south to northern California and east to Idaho, growing in cool, humus-rich soils under western red cedar, western hemlock, and Douglas-fir. Spreads by underground rhizomes to form extensive colonies carpeting the forest floor at 6–12 inches (15–30 cm) tall. Each stem bears a single large compound leaf divided into three fan-shaped to broadly wedge-shaped, deeply scalloped leaflets 2–4 inches (5–10 cm) across, dark green above and paler beneath. In April through June, slender naked stems 8–16 inches (20–40 cm) tall bear a single dense cylindrical spike 1–3 inches (2.5–8 cm) long of tiny, petalless white flowers consisting only of white stamens. The common name refers to the strong vanilla fragrance of dried leaves, produced by coumarin compounds; dried leaf bundles have traditionally been used as insect repellent. Non-toxic.

Native Range

Native to moist conifer forest understories of the Pacific Northwest — British Columbia south to northern California and east to Idaho and Montana — growing in cool, deeply shaded sites in humus-rich, well-drained to moist, acidic soil under western red cedar, western hemlock, and Douglas-fir.

Suggested Uses

Planted as a shade groundcover under conifers, in native woodland gardens, and forest restoration plantings in the Pacific Northwest at 18–24 inch (45–60 cm) spacing, allowing rhizome spread to fill in over 2–3 years. One of the most elegant native woodland groundcovers — large fan-shaped trifoliate leaves create a lush forest floor. Particularly effective under western red cedar and western hemlock in damp shade. Combine with Oxalis oregana, Trillium ovatum, Maianthemum dilatatum, and Polystichum munitum.

How to Identify

Identified by low-growing rhizomatous colonies of stems each bearing a single large trifoliate compound leaf with three distinctive fan-shaped to broadly wedge-shaped, deeply scalloped and wavy-margined leaflets 2–4 inches (5–10 cm) across — no other common PNW forest plant has this exact trifoliate fan-leaf form. In April–June, slender naked stems bear a dense cylindrical spike of tiny white petalless flowers (stamens only). Dried leaves emit a distinctive strong vanilla fragrance. The unique fan-shaped scalloped trifoliate leaf and vanilla-scented dried foliage are diagnostic.

Appearance

Size & Dimensions

Height6" - 1'4"
Width/Spread1' - 2'

Colors

Flower Colors

white

Foliage Colors

green

Fall Foliage Colors

yellow

Bloom Information

Bloom Period

~6 weeks
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Spring
Blooms April through June, producing slender leafless stems 8–16 inches (20–40 cm) tall tipped with a dense cylindrical spike 1–3 inches (2.5–8 cm) of small, white, petalless flowers consisting of exposed white stamens. The white spikes rise above the leaf carpet and attract small native bees and flies. Blooms reliably in the Pacific Northwest as the forest canopy begins to close in late spring.

Detailed Descriptions

Flower Description

white; tiny petalless flowers of exposed stamens only; dense cylindrical spike 1–3 inches on slender naked stem

Foliage Description

dark green above, paler beneath; three fan-shaped to broadly wedge-shaped, deeply scalloped leaflets 2–4 inches across per leaf; dried leaves emit strong vanilla fragrance

Growing Conditions

Sun Requirements

Partial Shade
Full Shade
Tolerates up to 3 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 7.0(Neutral)
357912
Soil Types
loampeatclay
Drainage
moist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Plant in full to partial shade in moist, humus-rich, acidic soil with a pH of 5.0–7.0. Prefers deep shade replicating forest floor habitat — tolerates only very light exposure. Requires consistent soil moisture; avoid drought. Mulch with leaf litter to retain moisture and mimic forest floor conditions. Spreads steadily by rhizome but is not aggressively invasive. Establish from rhizome divisions or container plants in early spring. Difficult to establish from seed.

Pruning

Requires no pruning. Remove dead or tattered foliage in late winter before new growth emerges. Dies back fully in fall and re-emerges from rhizomes in spring. Divide in early spring by digging sections of the rhizome mat and replanting into prepared humus-rich soil.

Pruning Schedule

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early spring

Maintenance Level

very low

⚠️ Toxicity Warning

Non-toxic