Xanthorrhoea Australis
(Grass Trees - Whroo State Forest Regional Victoria, Australia)
These examples are hidden in iron bark and are probably between 200 and 500 years old.
Grass trees were established in Australia tens of millions of years before the first Eucalyptus even existed. Some of the largest, multi-branched grass trees in Victoria are comfortably 800+ years old, and very occasionally they hit 1,000 years.
Their broader plant family shows up in the fossil record around 60–100 million years ago (Late Cretaceous).
The Xanthorrhoea lineage is considered one of the oldest surviving plant groups in Australia, evolving here back when the continent was still welded to Antarctica. Many botanists refer to them as “Gondwanan survivors”, meaning they’ve persisted since the age of megafauna and well before it.
Their age is hard to determine because the trunk height is influenced by fire history. If a grass tree gets burnt, the skirt burns off but the trunk remains and keeps stacking growth. But repeated intense fires can damage the crown and set growth back.
Their skirt of dead leaves (the “petticoat”) acts as insulation during fire. They don’t just survive fire — they expect it.
They rely on mycorrhizal fungi in the soil. If those fungi are damaged, the grass trees deteriorate quickly.
They grow slowly and are very tough. They survive drought, poor soil, and fire. They hate disturbance of their root system. Many die from root shock. When they die they leave a mat of material that looks like wood shavings.
