Grass Trees Guide
How to get the best out of your grass tree
Grass trees (xanthorrhoea) make a stunning visual display in any garden and are total unique from any other plant in the world. Their striking burnt black trunks and green foliage stand out both in the Australian bush and through our city landscapes. Growing at an extremely slow rate of approximately 3cm per year larger specimens can be well over 150 years old and any trunk at all could take as long as 10 years to form.
When choosing to have these epic plants in our gardens it is therefore vital to choose the correct specimen and know how maintain the health of plant throughout its life (or yours).
Step 1 – Choose wisely
To begin with it essential only to buy from those who know. Grass trees are a harvested plant meaning these are dug up from the ground and re-potted for sale. This process of transplanting grass trees needs to be performed by experienced and knowledgeable experts.
Rushing the process, not getting enough root structure, digging unsuitable plants, and not enacting a maintenance plan will result in a unstable plant that although may look good when it comes to market may only go backwards after you take it home.
So how do we know we have the best? Well, we have over 20 years of building a close relationship and understanding with our harvesters and their methods. We won’t accept second class service and we pay more for a premium product. Working with our harvester with have ensured a process where the plants are selected and dug extremely carefully. The plants are then inoculated with a mixture of fertilisers and microorganism stabilising products (a product which we encourage all our customers to use). They are then held for at least 6 months to ensure they recover from the harvesting process and they show strong root and new foliage growth. After the grass tree arrives in Melbourne we once again inoculated it and enact a management plant to observe and maintain its health before goes on sale.
No matter where you go to buy your grass tree you need to ask questions;
- Can you offer a firsthand grantee that this plant was harvested by a professional harvester?
- Has the plant been inoculated?
- What products can I use to maintain the health of the plant long term? (if they don’t have a microbe product to offer then you must question their experience with grass trees)
- How long from harvest has the plant being held for?
- How long have you being selling grass trees and what response have you had from your customers?
Once you are happy that you are buying from an experienced and good reseller then choose your grass tree. Look for plants that have nice full foliage which is bright and green. You should avoid plants that show signs of scale or root rot (black rings in the foliage of the plant). Equally avoid any grass tree that looks like it has been in the pot for a long time as these maybe root bound and potentially rotting in their pots. Think about the look you are after. Grass trees come with varying thickness of trunk from 10cm wide to a monstrous 50cm. Also the straightness or lack thereof in the trunk; some people want dead straight trunks but waving or leaning trunks are equally healthy and can be more of a feature.
Step 2 – Planting
There are two keys to planting grass trees;
1. Minimise any disturbance to the root structure
2. Ensure great drainage
Grass trees have sensitive roots structure that can be easily damaged by rough treatment and in the longer term can rot in stagnated water. To avoid these problems you first need to prepare where you are planting your grass tree.
For pots, the job is fairly easy. Just ensure that the drainage will not be blocked and that you use a premium potting mix.
For ground planting however the job can be a little more challenging. First consider the location. Grass trees like full sun to semi shaded positions and will not respond well in an area that is boggy or damp. Once you have your location you will best be served by performing a drainage test. (see here)
If you are not happy with the drainage then don’t fret there are options to better your drainage and get your plant where you want it.
The first is removing some of the soil already there. Dig down twice the depth of the pot your grass tree is in and twice as width. Fill this hole back is with a thin layer of scoria or stones to help with the drainage process. Then use a premium garden soil or potting mix to raise the depth of hole back up to the depth of the pot your grass tree is in. Then try another drainage test.
You can help drainage by planting your grass tree the top of a raised mound. Building a raised mound is extremely easy to do. Simply mound up a premium garden soil to increase the run off of water and encourage the soil to dry more quickly. A raised mound can be used in conjunction with the method above or can be a simple way of planting in extremely hard soil types. It also has the added benefit to raising the grass tree up and creating a more impressive feature.
Once you have prepared where you are going to plant then it is time to prepare the grass tree itself.
One thing a lot of people make the mistake of doing is pulling the grass tree out of the pot. Never do this! You will simply damage the roots and stress the plant. You should either simply cut the plastic pot away from the soil or, as we highly recommend, plant your grass tree with some of the pot still attached. Just cut off the bottom to help with drainage, put a few slits in the sides for the roots to grow out, and lose the rim of the pot for better presentation.
Next simply stick into the hole or pot you prepared earlier and back fill with premium soil or potting mix. As with most plants you should then give it a good soaking to remove air pockets from the soil before inoculating the plant with a microbe mix that you can receive in store. This will help the plant with betting it use to its new home and for large specimens a second mix should be given a couple of days later.
Do not fertiliser for the first couple of weeks and it won’t help the process and may in fact run the root structure.
Finally you should apply a thin layer of mulch.
Step 3 – Ongoing maintenance
Counter to the common belief grass tree will respond better to regular watering particularly in the first 12 months. This is why drainage in so important as it is really improbable that you can damage or kill your grass tree by over watering as long as the water is draining away and not becoming stagnate. It is however possible that you could kill your grass tree by under watering.
How much watering is really a case by case question as no two locations are ever going to be the same as there will always be differences in drainage, sunlight, wind and much more. Get in touch with us if you are concerned but just remember that the key is drainage; if your grass trees has great drainage you should not be able to over water it and therefore you shouldn’t have to worry just give it lots! Just water the soil only and not the foliage of the plant.
Fertilising is also important to keep the foliage is the best possible condition. You can use a range of fertilisers to feed your grass tree but we recommend sticking the A grade quality products such as Complete Focus and Dynamic lifter. You can use sea weed products as an additive feed but don’t use these products as a primary fertiliser as they lack some key ingredients.
We also highly recommend using our microbe mix on your grass tree every 6 months or so. This product is designed to encourage the microorganisms that live through the root structure of grass trees. Without these microorganisms the grass tree will slowly die back. In fact your grass trees show any signs of bad health then the first response should be to microbe the plant as soon as possible.
Every 8-10 years or so it is important to burn away the old dead foliage around the trunk of your plant. This old foliage once it builds up can become a hiding spot for pests and bugs that can in time hurt your grass tree. By burning this away you limit the opportunities for these pests to thrive. You also will be encouraging new growth and perhaps a new flower. To perform this task the best method is to tie the foliage of the plant up and wrap it with a damp cloth. Then wrap the trunk with some newspaper and get some matches. As it burns you should have some damp garden gloves on to just pat down the flames as you go to protect the crown from burning. Take it slow as you perform this action.