Xanthosia spp.

southern cross

Attracts Pollinators Attracts Butterflies Drought Tolerant Container Friendly

SunFull Sun – Part Shade

HardinessZones 9–10

Overview

Xanthosia spp. is a genus of about 20 small herbs and subshrubs in the carrot family, almost all native to Australia, with one species reaching New Zealand. Plants range from low, wiry perennials a few centimetres high to bushy subshrubs reaching about 1 m (3 ft), with green, often lobed or deeply divided leaves on slender stems. The small flowers are carried in compact umbels and are usually cream, white, or greenish, sometimes tinged pink, and in the well-known X. rotundifolia the flower cluster is framed by spreading bracts that form a cross, giving the name southern cross. Flowering comes mainly in spring and summer. Most species grow in heath, open woodland, and rocky or sandy sites on low-nutrient, free-draining, acidic soils, where they tolerate drought and exposure once established. The genus spans short-lived and longer-lived plants, so habit and lifespan vary between species. Wet, heavy, or fertile soils are poorly tolerated, and many species are sensitive to high phosphorus, like other plants of Australian heath. Growth is generally low and compact rather than vigorous or spreading.

Native Range

The genus is centred in Australia, where species grow across the south, east, and west of the continent and in Tasmania, with a single species in New Zealand. They occupy heath, open forest, granite outcrops, and sandy or rocky soils. X. rotundifolia of Western Australia is among the more widely recognised species.

Suggested Uses

Used in native, heath, rockery, and dry gardens on sandy acid soils, and in containers of free-draining mix. The small flower clusters suit cottage and pollinator plantings. X. rotundifolia is also grown for its cross-shaped flower heads in cut and dried arrangements.

How to Identify

Look for small Australian herbs or subshrubs with lobed or divided green leaves and compact umbels of tiny cream to greenish flowers. In X. rotundifolia, spreading bracts around the flower cluster form a clear cross shape. The umbel flowers and aromatic carrot-family foliage, combined with heath or woodland habitat, place the plant in Xanthosia spp..

Appearance

Size & Dimensions

Height4" - 3'3"

Width/Spread6" - 2'

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Spring Summer

Flowering is concentrated in spring and summer, roughly September to December in much of Australia. Small flowers are gathered into compact umbels, and in some species coloured bracts add to the display. Bloom continues over several weeks where conditions stay mild and moist.

Detailed Descriptions

Flower Description

cream, white, or greenish, sometimes pink-tinged

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range4.5 - 6.5(Acidic)

357912

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

1-2 years to flowering

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plants grow in full sun to light shade on sandy, gritty, acidic, free-draining soils, including low-nutrient ground. Once established they tolerate drought and exposure, while wet, heavy, or rich soils cause root rot and decline. Feeding is light and low in phosphorus, matching the needs of many Australian heath plants. Light frost is tolerated by most species, though hard freezes cause damage. Sharp drainage and a position that dries between waterings suit them. Few pests trouble them, but root rot follows poor drainage or overwatering.

Pruning

Light tip pruning after flowering keeps plants compact and bushy. Spent flower stems are trimmed to tidy the plant. Plants resprout from soft and semi-hard wood, so a gentle annual trim maintains shape.