Xanthorrhoea spp.
grasstrees
Overview
Xanthorrhoea spp., the grasstrees, is a genus of about 28 slow-growing perennials endemic to Australia. Plants form a dense crown of long, narrow, rigid leaves, each only a few millimetres wide but often 0.5-1 m (1.6-3 ft) long, arising from a short basal trunk. In trunk-forming species the trunk is built from tightly packed old leaf bases bound by resin and is frequently blackened by past fire; it lengthens only about 1-2 cm (0.4-0.8 in) a year, so a 3 m (10 ft) trunk may represent two to three centuries of growth. Some species remain trunkless. Flowering produces a tall woody spear topped by a dense cylindrical spike of small cream-white flowers; the whole structure can stand 2-4 m (7-13 ft) high and is rich in nectar. Flowering is often triggered by fire, to which the genus is highly adapted. Grasstrees grow on nutrient-poor sandy and lateritic soils in heath and dry forest and are very long-lived, with some plants estimated at several hundred years old. They are slow to establish, intolerant of root disturbance, and vulnerable to the soil-borne pathogen Phytophthora cinnamomi.
Native Range
Xanthorrhoea spp. is endemic to Australia, occurring in every mainland state and in Tasmania. Species grow in heathland, woodland, and dry sclerophyll forest, typically on sandy or gravelly soils.Suggested Uses
Xanthorrhoea spp. species are grown as long-lived architectural specimens in native, coastal, and low-water gardens, where the leaf crown and tall flower spears are prominent. They suit large rockeries and gravel gardens on free-draining ground. Mature, trunked plants are slow and costly to replace, so they are usually given a permanent position.How to Identify
Appearance
Size & Dimensions
Height1'8" - 16'
Width/Spread3' - 6'
Bloom Information
Flowering is irregular and often follows bushfire, most commonly in spring but varying with species and season. The spike opens its small flowers in waves over several weeks, drawing many insects and nectar-feeding birds. Plants may go several years between flowering events.
Detailed Descriptions
Flower Description
cream to whiteFoliage Description
green to blue-greenGrowing Conditions
Sun Requirements
Requires 6-12 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