Grass Trees: Iconic Australian Plants

Grass trees are iconic Australian plants. There are more than 60 different varieties of Xanthorrhoea or grass trees that are endemic to Australia. These tough, drought-resistant plants were and still are important to the native people of Australia. They are both a practical resource and one of spiritual significance.


Grass Trees: A Protected Species

Before discussing anything else about grass trees, it is important to note that they are a protected species. This means that you should not nip out, dig one up, and bring it home to plant in your garden. By the same token, if you need to clear an area where grass trees are growing, it is an excellent plan to contact a local licensed grower and have them carefully rescue these iconic plants before you do any other clearing. While they are there, you might also ask the rescue team if there are other plants that should be rescued before you proceed with your construction. Growers who are licensed to sustainably harvest native plants will probably be glad to add to their stock while keeping you out of a lot of hot water.


Planting Grass Trees

Grass trees can be grown from seed or carefully transplanted from a pot or rescued from construction sites, as described above. They are superb plants for low water or dry gardens, especially in soils that drain well. They are tolerant of a variety of soils, just as long as they are not excessively damp. With that said, Xanthorrhoea is dependent upon a specific type of mycorrhiza that assists them with extracting nutrients from the soil. Without this specialized symbiont, the trees will eventually sicken and die. This is another reason to get your grass tree from a licensed professional because he or she will help make sure that your grass tree has a nice supply of the symbiont and will instruct you in making sure that this natural team is properly installed on your site.

Grass trees can be grown from seed or they can be transplanted as young or mature trees. If grown from seed, you will have a bushy garden ornament with grass-like leaves. Grass trees are monocots that grow at around  ½ inch or 1 centimetre per year. Much of their initial trunk development is underground in the first years after germination. Licensed nurseries often sell rescued or harvested trees that have a developed trunk. They will usually pamper rescued trees for several months to make sure that they will survive the move. During this transition phase, they are likely to be housed in pots or grow bags where soil and water conditions can be carefully monitored.

When transplanting a grass tree obtained from a nursery, be sure to include the soil from its original container. That soil is likely to contain a colony of its essential mycorrhiza. Some sources say that you can encourage the colony by watering about once a month with water that has brown sugar added to it.


Encouraging Your Grass Tree to Bloom

Contrary to popular belief, you do not have to burn around your grass tree to get it to bloom. While many species of xanthorrhoea are adapted to fire, there are other ways to encourage your grass tree to produce a scape or bloom stalk. The first and best way is to promote good health. But it should be understood that with 60 different species of a grass trees, not all of them will bloom on the same schedule. The second consideration is the maturity of each plant. It might be as long as ten years before your grass tree will produce blossoms.

A third item to consider is the role fire plays in the Xanthorrhoea’s ecosystem, which is that it burns away the dead leaves and destroys any pests that might be living in them, and the ash acts as a fertilizer. The deal plant matter can be trimmed away with a hedge trimmer or even a chainsaw, and appropriate fertilizer can be added.


Pests and Diseases that can Affect Xanthorrhoea 

Grass trees are susceptible to scale, mealybugs, bardi grubs, root rot, anthracnose, and cinnamon fungus. If your grass tree seems to be failing for any reason, it is a good idea to contact the licensed nursery where you obtained your plant. Although these plants might seem like a “plant and forget” kind of garden growth, a weekly checkup can catch problems before they get too deep a toe-hold in your lovely grass tree.


Other Things that can Trouble Grass Trees

Two of the biggest problems for grass trees are too much water, especially when combined with too little drainage. Wet feet can cause root rot, and can open the way for other sorts of infection. Prevention and planning are the best methods, but if you discover that your grass tree is soaked too often for its comfort, you can dig a trench around it at a distance that exceeds its dripline by at least a foot and backfill the trench with coarse gravel. This works best if the water in the trench has someplace to go…such as to drain over into a bed of thirsty water-loving plants.

Chemicals can also be a problem. Runoff from lawn fertilizer can overload your grass tree with phosphates. In addition, grass trees have a low tolerance for saline.

Keep mulch back from the trunk area. Mulch is great stuff for preserving moisture, but it can promote pests that can invade the stem.

Finally, believe it or not, grass trees can suffer from drought stress. Even though they like well-drained soil and require minimal water, there comes a time when they need moisture.


Enjoy Your Grass Tree

Designer Trees is qualified to handle your rare or endangered trees. We are licensed to sustainably harvest rare plants, including Xanthorrhoea Glauca. We are exceptionally proud of our grass tree forest. Walking through it is like taking a step back in time. We invite you to browse our selection of young and mature plants, as well as to discuss the best placement for your iconic Australian trees.


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