tree

Blackwood

Acacia melanoxylon

The Story

Plant Bio

Acacia melanoxylon, the blackwood, is an upright, dense evergreen tree reaching heights of fifty to one hundred feet, developing a straight trunk with dark, deeply fissured bark. The mature canopy consists of leathery, lanceolate-elliptic phyllodes, though juvenile growth often retains bipinnate true leaves before transitioning.

In spring, the branches bear short clusters of pale yellow to cream-white globular flower heads resembling small pom-poms. This species is highly adaptable to varied soil types and exhibits high drought tolerance once established, but it is classified as invasive in coastal California where it escapes cultivation into native woodlands.

Uses & Benefits:

Features a dense, evergreen canopy of dark green phyllodes and pale yellow spring flowers, providing year-round structure.

Functions as an effective windbreak or erosion control barrier on slopes due to its robust, deep root system.

Provides pollen for generalist bees and beneficial insects, though it does not attract nectar-feeding birds like hummingbirds.

Essentials

At a Glance

Plant Type

Tree

Height

1180"

Width

470"

Light

Full Sun, Partial Sun

Zones

8, 9, 10

Water

Moderate

Humidity

Moderate

Lifespan

Long-lived

Native To

Australia

Toxicity

Mild Allergen

Bloom period

Spring – Early summer

In flower about 4 months of the year

Planting

How to Grow

Select a planting site in full sun to partial shade with well-drained sandy, loamy, or clay soil.
Dig a hole twice as wide as the root ball and of equal depth to ensure the trunk flare sits level with the surrounding soil.
Backfill with native soil without adding soil amendments, tamping lightly to remove air pockets, and water deeply.
Apply a three-inch layer of organic mulch around the root zone, keeping it several inches away from the trunk to prevent rot.

Pro Tip

Prune lightly immediately after spring flowering to shape the canopy; cutting heavily back into old, leafless wood prevents clean regrowth and can stall new shoots.

Keep It Thriving

Care Guide

Do

Water regularly during the first two growing seasons to establish a deep, resilient root system.
Check local invasive plant lists before planting near wild chaparral or coastal woodland interfaces.
Wear protective masks and gloves when pruning or milling wood to avoid irritation from wood dust.

Don't

Do not apply high-phosphorus fertilizers, as standard native-plant formulations or no supplemental feeding is preferred.
Do not plant in low-lying, poorly drained areas where standing water persists.
Do not cut back into bare, old wood during structural pruning.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Mulch
Pest Check
Plant
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

WindbreakShade TreeErosion ControlScreening

Companion Plants

Ceanothus thyrsiflorus Heteromeles arbutifolia Arctostaphylos densiflora

Multiply

Propagation Methods

Good to Know

Common Questions

Blackwood questions

What zones can Blackwood grow in?

Blackwood is hardy in USDA Zones 8–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Blackwood deer resistant?

Not reliably. Deer may browse Blackwood, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does Blackwood bloom?

Blackwood typically blooms in spring through early summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Blackwood need full sun?

Blackwood does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Blackwood drought tolerant?

Yes — once established (usually after the first full season), Blackwood handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.