Fernbush

Sun

Full sun; tolerates light shade but flowers less freely and may become open and leggy.

Water

Water regularly during establishment, letting the soil dry between soakings. Established plants need little supplemental water except during prolonged drought.

Soil

Well-drained sandy, gravelly or rocky soil; tolerates poor and alkaline soils. Avoid waterlogged ground and heavy soil that stays wet in winter.

Height

3-6 ft (0.9-1.8 m)

Spread

3-6 ft (0.9-1.8 m)

Flowers

Creamy-white flowers in upright, branching clusters from early to late summer, depending on climate.

Foliage

Finely divided, fern-like green to grey-green leaves with a resinous scent when brushed. Semi-evergreen in mild climates and largely deciduous in cold winters.

Growth

Moderate

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Wildlife
• Low allergen
• Fragrant

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.6 ft (0.5 m)

2. After 1 year

   2.2 ft (0.67 m)

3. After 2 years

   2.8 ft (0.84 m)

4. After 3 years

   3 ft (1 m)

5. After 5 years

   4 ft (1.4 m)

   full size

About 5 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US

Growth rate

Moderate

• Plant with the root crown level with the surrounding soil in a sunny, freely draining position.
• Water deeply through the first growing season, allowing the soil to dry between waterings.
• Once established, avoid frequent irrigation, especially in cool weather.
• Use a thin gravel mulch and keep it clear of the stems.
• Do not routinely fertilize; rich feeding encourages loose growth.

Pruning. In late winter or early spring, remove dead or damaged wood and lightly shorten wayward shoots to retain a rounded shape. Avoid regular shearing; remove spent flower clusters after flowering only if you want a tidier appearance.

Early spring

Remove winter-damaged stems and lightly shape before strong new growth begins.

Spring

Plant in well-drained soil and water thoroughly; spring planting is safest in cold or winter-wet gardens.

Late spring

Check newly planted shrubs and water when the root zone has begun to dry.

Summer

Enjoy the flowers and visiting insects; water established shrubs only during extended dry spells.

Late summer

Remove faded flower clusters if desired, or leave some to develop seed.

Autumn

Clear fallen debris from around the crown and check that winter rain can drain away freely.

• Use as a medium-sized structural shrub in a gravel garden, contrasting its fine foliage with boulders and coarse-leaved plants.
• Combine with penstemons, yarrows and ornamental grasses in a sunny, low-water border.
• Plant in loose groups on a dry slope where its rounded form can develop without clipping.
• Place beside a sunny path where its scented foliage can be appreciated without obstructing access.

Garden styles it suits: Desert / xeriscape, Dry gravel garden, Southwestern, Mountain lodge, Pollinator garden and Low-maintenance.

Plant it with: Penstemon, Yarrow, Little bluestem, Blue grama, Russian sage and Sulphur buckwheat.

Wildlife: The flowers attract bees and other pollinating insects. Its branching growth also provides shelter for small garden wildlife.

• Root and crown rot in persistently wet soil: improve drainage or move the plant to a raised, gravelly position; reduce irrigation.
• Sparse flowering and leggy growth in shade: move to full sun and avoid high-nitrogen fertilizer.
• Poor establishment from drought: water the original root ball deeply during the first season rather than assuming a young plant is already drought-tolerant.

Not known to be toxic to people, cats, dogs or horses, but reliable species-specific safety information is limited. No particular poisonous part is established; treat it as an ornamental rather than an edible plant.

• Sweetfern (Comptonia peregrina)

  Sweetfern has simple, deeply lobed leaves rather than fernbush's finely divided leaves, and bears inconspicuous catkin-like flowers instead of showy creamy-white clusters.

• False spiraea (Sorbaria sorbifolia)

  False spiraea has pinnate leaves with much larger, sharply toothed leaflets and often forms suckering colonies; fernbush has much finer foliage and is adapted to drier soil.

The common name describes its fern-like foliage, while the species name millefolium means 'thousand-leaved', referring to the finely divided leaves.

Propagation. Grow from seed sown in a free-draining medium, or take softwood to semi-ripe cuttings in late spring or summer. Seed-grown plants may vary in habit.

Accepted botanical name

Chamaebatiaria millefolium

In the US and Canada

Native in the lower 48 states.

Native range

Arizona, California, Idaho, Nevada, Oregon and Utah.

Measured

Soil pH 7 to 8. Average height 122 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.