Some species grow slowly (0.8–6 centimetres or 0.31–2.36 inches in height per year), but increase their rate of growth in response to season and rainfall.

[6][4] Xanthorrhoea is part of the family Asphodelaceae, containing related genera such as Aloe, Alstroemeria, Gasteria, Haworthia and Hemerocallis (to name a few), but is placed within its own monotypic subfamily, the Xanthorrhoeoideae.

[citation needed] Some plant classification systems, such as Cronquist,[10] have included a wide range of other genera in the same family as Xanthorrhoea.

However, future anatomical and phylogenetic research supported the views of Dahlgren,[11] whom regarded Xanthorrhoea as the sole taxon of the family Xanthorrhoeaceae sensu stricto, which is now treated as a subfamily, Xanthorrhoeoideae.

Some thought that Aboriginal peoples used the name balga because the trunk blackened after a bushfire resembles a child-like black figure.

[17] In South Australia, Xanthorrhoea is commonly known as yakka, also spelled yacca and yacka, a name probably from[14] the Kaurna language (Yakko, or alternatively Kurru).

According to the World Checklist of Selected Plant Families, as of September 2014[update] the following species are accepted:[1] Grasstrees grow in coastal heaths, and wet and dry forests of Australia.

It survives in the poorest soils, with a shallow root system, enabling it easily access nutrients from decaying litter, while storing all the food reserves in its stem.

If a fire breaks out, the grass tree has a special physiological adaptation called thermal insulation that helps protect the plant.

The grass tree holds its thick, dead leaves around its stem which serves as insulation, and helps to protect the plant against the heat of the fire.

Phytophthora cinnamomi is a discrete soil borne pathogen that attacks and destroys vascular root systems, causing hosts to perish through lack of nutrients and water.

The most successful examples of transplanting have been where a substantial amount of soil, greater than one cubic metre (35 cu ft), has been taken with the plants.

[citation needed] The genus Xanthorrhoea, more commonly known as the grass tree, is an iconic plant that epitomizes the Australian bush in its ability to live in poor nutrient soils and respond to wildfire.

[26] The flowering spike may be utilised as the lightweight handle of a composite spear with a hardwood sharp shaft inserted into the end.

[28] The resin from Xanthorrhoea plants is used in spear-making[29] and is an invaluable adhesive for Aboriginal people, often used to patch up leaky coolamons (water containers) and even yidaki (didgeridoos).