Artemisia douglasiana (California mugwort)

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Artemisia, Genus, douglasiana, Species,

Genus & species

California mugwort

Asteraceae Western North America

Deer Resistant Drought Tolerant Fragrant (strong)

SunFull Sun – Part Shade

WaterMedium · drought-tolerant

HardinessZones 6–10

Overview

Artemisia douglasiana is an aromatic, rhizomatous herbaceous perennial reaching 2-7 feet (0.6-2.1 m) tall, spreading by underground rhizomes to form colonies. Stems are erect, grooved, and often reddish, becoming woody at the base in older plants. Leaves are lance-shaped, 2-6 inches (5-15 cm) long, dark green and nearly smooth above with dense white-woolly hairs beneath; upper leaves are mostly unlobed while lower leaves bear a few coarse lobes or teeth near the tip. Crushed foliage releases a strong sage-like scent. Small, nodding, greenish to yellowish flower heads grow in narrow leafy spikes from June through October and are wind-pollinated. Tiny seeds follow and disperse on wind and water. The rhizomes spread aggressively in moist ground, forming dense stands that crowd other plants. Foliage dies back to the rhizome over winter in colder areas. New shoots emerge along the rhizome each spring, widening the colony by 1-2 feet (30-60 cm) per year.

Native Range

Native to western North America, from Washington south through California to Baja California and east to Idaho and Nevada. Grows along streambanks, ditches, moist canyon bottoms, and disturbed damp ground, from sea level to about 7,000 feet (2,100 m).

Suggested Uses

Planted in native, riparian, and habitat gardens, and for streambank and slope stabilization where its rhizomes bind soil, at 24-36 inch (60-90 cm) spacing. The aromatic foliage is used in cultural and traditional practices. Its spreading rhizomes make it suited to large naturalized areas rather than small mixed beds.

How to Identify

Recognized by lance-shaped leaves 2-6 inches (5-15 cm) long that are dark green above and white-woolly beneath, releasing a sage-like scent when crushed. Lower leaves carry a few coarse lobes near the tip while upper leaves stay narrow and unlobed. Narrow leafy spikes of small nodding greenish flower heads separate it from the more deeply divided foliage of Artemisia vulgaris.

Appearance

Size & Dimensions

Height2' - 7'

Width/Spread2' - 4'

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~16 weeks

Flowers: June–October

Summer Fall

Blooms from June through October, with timing shifting later at higher elevations. The small wind-pollinated heads open over a long period along leafy spikes. Flowers are greenish and inconspicuous. Seed sets through late summer and fall.

Detailed Descriptions

Foliage Description

dark green above, white-woolly beneath

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 5-10 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 Range5.5 - 7.5 (Acidic to alkaline)

3579

Soil Types

clay loam sand

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun to part shade in moist to seasonally wet soils and tolerates clay, sand, and periodic flooding. Established plants tolerate summer drought by slowing growth, though they stay leafy only with some moisture. The rhizomes spread quickly in damp, loose soil, so the colony widens each year unless contained. No fertilizer is needed, and rich soil increases spread. Few pests or diseases trouble it. Cut back old stems in late fall or early spring as new shoots emerge from the rhizome.

Pruning

Cut stems to the ground in late fall or early spring before new growth. Shearing in early summer reduces height and bushiness on tall stems. Removing rhizome pieces from the edge of the stand each year limits its spread.