Xanthorrhoea johnsonii (Johnson’s Grass Tree) is a perennial monocot that is native to Eastern Australia. Johnson’s Grass Trees are grown as ornamentals and feature plants across a wide range of soils and climates in Australia. They are drought and frost tolerant, require little maintenance and produce white flowers from Autumn to Summer.
Suitable for Temperate, Dry, Sub-Tropical and Tropical climates.
Xanthorrhoea johnsonii is also called Steel Grass due to the tough older leaves which can bent easily and is ideal for floral design.
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Growth
Xanthorrhoea johnsonii is a slow-growing monocot that reaches a maximum height of around 5 metres (16 feet) by a width of up to 2 metres (7 feet). Johnson’s Grass Trees are adaptable to a range of soils and are frost and drought tolerant.
Once established, they require very little maintenance and do well in all climates across Australia.
The form of the plant resembles a tree, with very long grass-like, leaves that emerge from the central base. Mature plants can produce creamy-white flowers that bloom from Autumn through to Summer. They appear on upright spikes that can reach 2.5 metres (8 feet) and are more prolific after bushfires.
A slow-growing tree, Black Boy Grass Trees may take between 15-20 years to reach full maturity.
Note: Germination instructions can be found in the ‘Germination Instructions Tab’ below. Upon purchase you will receive these detailed instructions via email so that you have a permanent record.
FAMILY:
Xanthorrhoeaceae
CLIMATE:
Temperate, Dry, Sub-Tropical and Tropical
TEMPERATURE RANGE:
-5 to 45°C / 23 to 114°F
SOIL TYPE:
Suitable for most types of soil, well-draining preferred.
LOCATION:
Full Sun
HEIGHT:
Up to 5 metres (16 feet)
WIDTH:
2 metres (7 feet)
pH:
5.5-7
GROWTH TYPE:
Perennial Monocot
WATER REQUIREMENTS:
Low
POLLINATION:
Birds & Bees.
MATURITY:
15-20 years
GERMINATION RATES:
84-92%
GERMINATION TIME:
4-8 weeks
GERMINATION DIFFICULTY:
Easy-Medium
SEEDS PER GRAM:
45
MEDICINAL QUALITIES:
No
WEED POTENTIAL:
No
FACTS ABOUT XANTHORRHOEA JOHNSONII (Johnson’s Grass Tree)
Xanthorrhoea johnsonii is named after Lawrence Johnson who was a taxonomic botanist who was awarded the Order of Australia for his services to botany. Throughout his career he described 286 new species and worked with the Royal Botanical Gardens in Sydney for over 50 years.
Like other plants in the Xanthorrhoea genus, the Johnson’s Grass Tree is immune to fire and instead will grow more vigorously afterwards.
