Grass Trees are neither Grass, nor Trees.
There are a number of tree-like plants that are known as grass trees. Four stand out as general types. These are the Mexican Grass Tree, Dasylirion longissimum; Dracophyllum, which resemble dragon trees but are a different kind of plant; Richea pandanifolia or the giant grass tree found in Tasmania; Xanthorrhoea, which is endemic to Australia; and Kingia Australis, which is similar in appearance to Xanthorrhoea, but is completely unrelated and found in Southwest Australia.
All of these except dracophyllum, are monocots meaning that when they emerge from the seed, they have only one primary leaf. Dracophyllum are dicots, meaning they have two primary leaves when they emerge from the seed. The common feature among all these plants is that they develop what appears to be a stem or trunk, and it is topped with rosettes of leaves that resemble clumps of grass in appearance. All do well in water-conserving gardens, prefer good drainage, and are usually hardy growers once established.
Xanthorrhoea are uniquely Australian. If fossilized evidence is accurate, they first appeared around 30 million years ago. They are admirably adapted to Australian climate and soil, including its tendency to have periodic brush fires. While fire is not essential to grass trees, it will stimulate some types into blooming. Not all species of Xanthorrhoea can survive burning, and even the toughest ones can have some trouble with huge, extremely hot fires.
In addition to being admirably adapted to the climate and soil, grass trees provide food and shelter to a broad variety of native species. Humans seem to have begun inhabiting Australia around 40,000 years ago. By the time European settlers arrived, the aboriginal occupants of the island continent had found many uses for Xanthorrhoea. They brewed a sweet drink from the flowers, used the sap as glue, made fire starting sticks from the bloom stalk, as well as using the hardened stalks as spears.
An article in Beating Around the Bush, published September 21, 2018, points out that Australian grass trees are neither grass nor trees. Although they are monocots, as are cereal grasses and bamboo, they are actually more like the lily family, particularly day lilies.
There are 28 distinct species of grass tree that are native to Australia. They include: X. australis, X. johnsonii, X. preissii, to name four well-known types. But perhaps one of the best known, and certainly the hardiest of the grass trees, is X. glauca, sometimes simply referred to as the Glauca Grass Tree.
Glauca Grass Tree
Shared Characteristics of Xanthorrhoea:
While there are a broad variety of Xanthorrhoea, they all share some characteristics.
- A monocot puts up one initial leaf when sprouting, instead of two.
- The plant puts up a roseate of stiff leaves that slowly bend over, and point toward the ground. In the case of the grass trees, these stiff leaves slowly plaster together, sealed by the sticky sap, to form the trunk.
- They put up a single bloom stalk. Although different species might have slightly different sorts of blooms, they all form on a stalk.
- Grass trees are amazingly useful. They tend to provide nectar and pollen for pollinating birds and insects. The long, narrow leaves can frequently be processed to produce fibers. The roots are frequently used in making soap or medicine. The sap makes an excellent glue.
- They are extremely hardy. Once established, they require little care and can withstand a wide range of temperatures.
Mexican Grass Tree:
Similar plants, such as Yucca Filifera, Yucca Rostrata, Joshua Trees, banana yucca, yucca flacida, and Mexican grass trees can be found Mexico and the southern parts of the United States, sometimes thriving as far north as Missouri. Mexican grass trees, however, are members of the dasylirion family Like the Australian species, these various plants have many uses, frequently providing food, medicine, and even fibers when correctly processed.
These are only a few of the many sorts of plants that are given the common name, “grass tree.” Although folk names for plants can be confusing, these giant “not grass, and not tree” growths are universally fascinating.