Mimosa

Tree

Acacia dealbata

Mimosa

Also known as: Acacia decurrens var. dealbata, Racosperma dealbatum

A fast-growing evergreen tree with fern-like silver-grey foliage and clouds of fragrant yellow pom-pom flowers in late winter.

  • Full sun
  • 6–12 m (20–39 ft)
  • 2.5–4 m (8–13 ft)
  • H3 · Zone 9
  • January–March
  • Evergreen
  • RHS Award of Garden Merit

Overview

Also known as mimosa or silver wattle, this Australian tree brings an early, sweetly scented flush of bright yellow flowerheads above finely divided, silvery, fern-like leaves from January to March, often before anything else in the garden is in flower. It is best treated as a plant for the mildest, most sheltered UK gardens: a warm, south- or west-facing wall out of cold winds gives it the best chance of coming through a typical winter, and young plants benefit from fleece in their first few years. In colder inland or northern gardens it is safer grown in a large pot that can be moved to a frost-free spot for winter.

At a Glance

Sun Full sun
Height 6–12 m (20–39 ft)
Spread 2.5–4 m (8–13 ft)
Hardiness H3 · Zone 9
Flowers January–March
Soil Loam, Sand
Moisture Moist well drained
Habit Spreading, Upright
Water Moderate
Maintenance Moderate

Growing Conditions

Min. Temperature -5°C (23°F)
pH Range 6–7
Fertility Average
Drainage Free Draining

Aspect Suitability

  • South-facing
  • West-facing

Site Tolerance

  • Coastal
  • Drought

Soil Tolerance

  • Sandy
  • Loam
  • Acid
  • Neutral pH

Foliage

Acacia dealbata (Mimosa) foliage
Acacia dealbata (Mimosa) foliage
Persistence Evergreen
Colour Silver, Grey-green, Green
Leaf shape / texture bipinnate_ferny
  • Architectural foliage

Foliage interest: 12 months of the year

Seasonal Timeline

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flowering
Foliage
Fruiting
Propagate
  • Flowering Jan Feb Mar
  • Foliage 12 months of the year
  • Fruiting Jul Aug
  • Propagate Mar Apr Jul Aug

Maintenance Calendar

  • Mar Remove any frost-damaged tips once new growth confirms live wood
  • May Lightly shape after flowering, avoiding cuts into bare old wood
  • Jun Water deeply while establishing
  • Oct Mulch the root area before winter
  • Nov Fleece young or newly planted trees during hard frosts

Garden Design

Works well in: Mediterranean, Modern / Contemporary, Tropical / Exotic, Wildlife-friendly

Give it the warmest, most sheltered spot available - a south-facing wall corner works well - and underplant with drought-tolerant Mediterranean shrubs that share its need for sharp drainage.

Companion planting: Mediterranean shrubs, Grasses, Spring bulbs

Wildlife Value

  • Bees
  • Other pollinators
  • Shelter

Safety

No well-established major toxicity; resents hard pruning back into old wood, so shape lightly and early.