shrub

Mottlecah

The Story

Plant Bio

Eucalyptus macrocarpa, known as the mottlecah, is a sprawling, multi-stemmed mallee shrub endemic to the dry sandplains of south-western Western Australia. It develops a woody subterranean lignotuber from which it can regenerate after fire or severe damage.

This species is distinguished by its sessile, powdery silver-grey leaves that clasp the stems in opposite pairs and emit a strong menthol scent when crushed. In winter and spring, it produces solitary red flowers up to ten centimetres across, followed by exceptionally large, woody, glaucous seed capsules.

Uses & Benefits:

Grown for its striking powdery silver-grey foliage and massive, bright red flowers.

Functions as an effective windbreak in second-line coastal or arid landscapes.

Provides a valuable source of nectar for native honeyeaters and insect pollinators.

Essentials

At a Glance

Plant Type

Shrub

Height

157 inches

Width

472 inches

Light

Full Sun

Zones

8, 9, 10

Water

Low

Humidity

Low to moderate

Lifespan

Long-lived

Native To

Western Australia

Toxicity

Foliage may cause skin irritation

Bloom period

Winter – Summer

In flower about 7 months of the year

Planting

How to Grow

Select a planting site in full sun with exceptionally well-drained sandy or gravelly soil.
Dig a hole twice as wide as the root ball but of the same depth, ensuring the plant is not buried deeper than its nursery soil level.
Backfill with native soil, firm gently, and water in thoroughly to settle the soil around the roots.
Apply a thin layer of gravel mulch around the base, keeping it clear of the main stem to prevent collar rot.
Water sparingly during the establishment phase, then cease regular watering once the root system is established.

Pro Tip

Plant in elevated mounds of coarse sand or gravelly loam to ensure rapid drainage, as summer moisture combined with warm soils triggers fatal Phytophthora root rot.

Keep It Thriving

Care Guide

Do

Ensure absolute, sharp soil drainage to prevent root rot.
Grow in a Mediterranean or dry-summer climate with low humidity.
Prune minimally, only to shape or remove deadwood.

Don't

Do not plant in heavy clay or poorly drained soils.
Do not overwater, especially during warm summer months.
Do not use heavy conventional chemical fertilisers high in phosphorus.

Seasonal Care Calendar

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

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Specimen plantingDryland gardensNative gardensWindbreaks (second-line coastal)

Companion Plants

Banksia species Grevillea species Westringia fruticosa

Multiply

Propagation Methods

Good to Know

Common Questions

Mottlecah questions

What zones can Mottlecah grow in?

Mottlecah 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.

When does Mottlecah bloom?

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

Does Mottlecah need full sun?

Mottlecah does best in full sun (6+ hours).

Is Mottlecah drought tolerant?

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