Grass Trees

Grass trees can be tricky at times, but there are some simple rules to follow.

Grass trees (also known as blackboys) are indigenous to Australia. They are slow growing but very long lived plants that develop a thick trunk formed by a mass of old leaf bases held together by natural resins. It takes 30 or more years for the leaf tufts to rise above the trunk. Long spear like flowers are produced appearing brown in colour, these are densely packed with small white flowers.

The flower spikes are produced sporadically, mainly developing in the spring months and in their natural habitat, after bushfires.


When Grass Trees are harvested from their natural environment the dry, heavy soil surrounding their root system is also dug up as this contains a bacteria which protects these plants from pest and disease. When you purchase a Grass Tree you will notice that the pot it is planted in is extremely heavy.

When planting your Grass Tree it is extremely important to keep rootball intact, much of the soil will fall away when you knock the tree out of its pot. A good way to plant them is to cut the base from the pot and the top, if it has a large rim and this will ensure that the soil doesn’t fall away.

Grass trees must be planted in extremely well drained soils; much of the soil in Melbourne is quite clayey and poorly drained.

To provide a well drained environment for your Grass Tree create a raised mound 2-3ft high x 2-3ft wide and plant your Grass Tree high up in the mound.

To ensure excellent drainage, an agricultural pipe can be laid at the base of this mound, planting in organic soil mixes and 3 way soil mixes should be avoided, please refer to our Wet Feet Kills Information Sheet for further instructions.

Grass trees grow in reasonably alkaline soils. As much of Melbourne’s soil is acidic it is important to apply ½ Kg/m2 of Dolomite lime each winter.

Grass trees thrive in full sun and should be fed sparingly, twice a year, with Devotion™ Time Release Fertiliser at half the recommended rate. If grown in seaside areas water any salt residue off your Grass Trees weekly.