California flannelbush

Sun

Full sun; shelter from cold, drying winds in cooler regions.

Water

Low once established. Water young plants carefully during establishment, then keep established plants mostly dry in summer.

Soil

Very well-drained sandy, gravelly or rocky soil; tolerates poor soil and a range of pH levels. Avoid heavy, wet ground.

Height

10-20 ft (3-6 m)

Spread

8-15 ft (2.4-4.6 m)

Flowers

Large golden-yellow flowers in spring and early summer, sometimes followed by scattered later flowers.

Foliage

Evergreen. Leathery, rounded to shallowly lobed dark-green leaves with densely hairy, pale undersides; leaves and young stems carry irritating hairs.

Growth

Fast in suitable conditions.

Care needed

Medium

• Pollinators
• Deer resistant
• Drought tolerant
• Heat tolerant
• Wildlife

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

Difficulty

Hard

Toughness

Needs looking after

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

1. Planting day

   1.8 ft (0.54 m)

2. After 1 year

   6 ft (1.8 m)

3. After 2 years

   10 ft (3 m)

4. After 3 years

   14 ft (4.2 m)

5. After 5 years

   15 ft (4.5 m)

   full size

About 3 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

Mildly toxic: may upset a stomach

Native to

the US

Growth rate

Fast

• Plant while small in a sunny, freely draining position; avoid moving established plants.
• Water deeply but infrequently during establishment, allowing the soil to dry between waterings.
• Keep established plants away from lawn sprinklers and regularly irrigated borders, especially in summer.
• Do not routinely feed; rich soil and heavy feeding encourage soft growth.
• Keep the stem base clear of mulch and use a light gravel mulch if needed.
• Wear gloves, long sleeves and eye protection when handling or pruning.

Pruning. Prune lightly just after the main flowering flush to shorten wayward shoots and develop a balanced framework. Avoid hard cuts into old, bare wood, which may not regrow reliably.

Spring

Plant in colder parts of its range once severe frost has passed, keeping the root ball intact.

Late spring

Check young plants for dry soil and water only when needed; avoid keeping the root zone continually moist.

Early summer

After the main flowering flush, lightly shorten stray shoots while wearing protective clothing.

Summer

Keep established plants largely dry and redirect nearby irrigation away from their roots.

Late summer

Take semi-ripe cuttings if you want to try propagating a particularly good plant.

Autumn

Plant in mild, dry-summer climates where winter soil drains freely; clear fallen leaves from the stem base.

Winter

Check for standing water around the roots and protect young plants during unusually severe cold.

• Use as a specimen on a sunny, dry bank where its spreading branches have room.
• Train against a sunny, sheltered wall in cooler gardens, keeping branches clear of windows and paths.
• Combine with manzanitas and California lilacs in a dry California-native shrub planting.
• Place behind low silver-leaved shrubs in a gravel garden for a strong spring display.

Garden styles it suits: California native, Mediterranean, Desert / xeriscape, Dry gravel garden, Wildlife garden and Modern Mediterranean.

Plant it with: Manzanita, California lilac, Cleveland sage, California buckwheat, Rockrose and Lavender.

Wildlife: Flowers provide pollen for bees, including native bees. The branching canopy offers cover for small birds.

• Root and crown rot: often follows poor drainage or regular summer irrigation; improve drainage before planting and keep established plants away from sprinklers.
• Frost injury: young shoots may die back in severe cold; choose a sheltered site and wait until spring growth reveals the damage before pruning.
• Wind damage: fast-growing branches can split or break; provide shelter and develop a balanced framework with light formative pruning.
• Skin and eye irritation: hairs shed during handling and pruning; wear protective clothing and keep the plant away from seating areas and narrow paths.

Not known to be poisonous to people, cats, dogs or horses, although species-specific ingestion information is limited. Hairs on leaves, stems and seed capsules can cause substantial skin and eye irritation and may irritate the mouth if chewed; do not treat any part as edible.

• Mexican flannelbush (Fremontodendron mexicanum)

  Typically has larger, more deeply lobed leaves and larger, more orange-yellow flowers. Garden hybrids between the two species can be difficult to identify by appearance alone.

Fremontodendron honours the American explorer John C. Frémont, californicum refers to California, and flannelbush describes the soft-looking hairs covering its leaves and stems.

Propagation. Grow from seed after scarifying the hard seed coat, following a reliable seed supplier's treatment instructions. Semi-ripe cuttings taken in late summer are another option, but rooting can be difficult; avoid disturbing roots when potting on.

Accepted botanical name

Fremontodendron californicum

In the US and Canada

Native in the lower 48 states.

Native range

California and Mexico Northwest.

Measured

Soil pH 7 to 7.5. Average height 305 cm.

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