Eucalyptus Tree Care
This guide will teach you how to care for a eucalyptus tree in your garden, in a pot or as a houseplant. Special attention is given to the growing of eucalypti in cold climates that are outside of the their natural range.
By a cold climate I mean any climate that is too cold for olive trees. People tend to plant olive trees wherever they will grow, especially in climate zones where they just-just survive. If you find olive trees planted in gardens in your area then you have dozens of eucalypti to choose from! If not then you still might have a good amount of species to choose from, depending on just how cold your climate is. The hardiest eucalypti are said to withstand temperatures below -20°C.
With over seven-hundred species in the genus (“Eucalyptus,” 2021) and a natural range that stretches from the snowy mountains of Australia to the tropical rainforests of Papua New Guinea — there are meant to be exceptions to this guide.
The information provided reflects the best of my knowledge at the current time. I am learning more with every eucalypt I grow and continue to update this guide accordingly.
- 1. General Eucalyptus Care
1. General Eucalyptus Care
The two most important factors for growing a healthy eucalypt is enough space for the roots and lots of sun. Only if both factors are met will your tree thrive.
Eucalyptus roots grow extremely fast and don't like being cut or disturbed. For a potted eucalypt, this means that once the roots have circled the inside of the pot more than once the tree is root-bound and starts strangling itself. On saplings this can be corrected to some degree while the roots are still soft but the larger the tree grows the more severe the problem becomes. Once the roots get too hard to correct without them breaking the tree is doomed. Pruning the roots to correct this is not a reliable option as the amount of pruning required will kill most species.
When planted in the ground, a small sapling that’s not root-bound will establish quickly and outgrow a much bigger, root-bound tree. As a result of the superior growth and faster establishment it will also be hardier, even if it's smaller at first ("Eucalyptus Growth Rate," 2004).
A root-bound tree will never establish the same root system as a tree that was never root-bound. The roots don't correct themselves as they grow. Some trees can recover from being root-bound but most eucalypti have a hard time recovering. The struggle to recover may result in weaker growth throughout the tree's lifetime and presents a danger of it being blown over by strong winds. Some of the tropical and subtropical species of eucalyptus seem to be less finicky about their roots ("Eucalyptus Growth Rate," 2004).
A eucalypt grown in a normal pot will quickly become root-bound and shouldn't be planted in the ground anymore. You will have to discard your pot-grown tree once it gets too big to pot up. If you want to keep the option of planting it in the ground open, you should use a specialized pot (e.g., Air-Pot, Root Pouch) that prevents the roots from circling ("Growing in Containers," n.d.). Most specialized pots don't look good but you can put them inside a nice pot. Just make sure to leave a few centimeters between the walls of the two pots and that they still drain well.
Look Before You Buy
Don't buy a root-bound tree! In other words, don't buy a tree in a normal pot unless it's still a sapling. Knowledgeable nurseries will grow their eucalypti in specialized pots, allowing you to start out with a thriving tree that's not root-bound.
Your eucalypt should be grown in a spot where it gets direct sun for most of the day. Not enough sun results in a weak tree that produces soft growth. The resulting growth is less frost tolerant and doesn't look as nice as what is produced with enough sun. While there are some species that tolerate moderate shade, like E. neglecta and E. crenulata ("Where to Plant," n.d.); all of them thrive in a sunny spot. If you don't have a sunny spot then pick a species known to be shade tolerant or use a grow light (when grown as a houseplant).
1.3 Soil & Nutrients
Eucalypti tend to thrive in a low nutrient soil with good drainage. However, this does not mean that they will not grow well in the nutrient-rich soil found in a lot of gardens. When planting them in the ground I find it better to choose a species that suits your soil then to try to adjust your soil to the needs of a specific species. The drainage of a particular site is of far greater importance than the soil pH or the nutrients it contains. If you have a site with poor drainage then it's important to choose a species that is known to tolerate poor drainage. If your site drains well then you can plant any species, as even those that tolerate poor drainage will thrive in a well-draining site.
Because of their low nutrient requirements; eucalypti don't need to be fertilized when planted in the ground. They benefit when the area around them is mulched (I use pine bark) and kept free of other plants, especially grass. This reduces competition for nutrients as the majority of eucalyptus roots grow withing the top 30-40cm of the soil ("Care After Planting," n.d.). A good layer of mulch also helps protect the roots from freezing in the winter.
For a potted eucalypt, I recommend mixing one part sand with two parts potting soil. If you plan to keep your eucalyptus as a houseplant or live in a rainy area then you can do a half-and-half mix. The soil used should be low in nutrients and not contain any added fertilizers. Mulching will also benefit a potted eucalypt and reduces the frequency of waterings needed. You may eventually need to fertilize a pot-grown grown eucalypt, especially if you are taking cut foliage from it. Use a fertilizer that contains trace elements, is low in nitrogen and phosphate, and contains high levels of potassium ("Care After Planting," n.d.). If you are unsure about fertilizing; pot up, don't fertilize.
In most climates eucalypti only need to be watered when kept in a pot and while they are establishing.
After planting a eucalypt in the ground you need to keep an eye on it to make sure it doesn't dry out. You should water it enough to keep it from wilting, but not much more. By only watering when absolutely necessary you are helping it establish a deep root system that is not dependent on you.
A potted eucalypt in a good soil with proper drainage can be watered daily during the growing season. This will produce the best growth. During the winter the soil should just be kept slightly moist. You can let the soil dry out now and again but don't let it get to the point where the leaves wilt ("Growing in Containers," n.d.).
It's easy to kill a eucalypt by over-watering it when kept as a houseplant. Go easy on the watering and keep the soil on the dry side indoors.
Eucalypti are not trees that should be planted in the garden on a whim. You will need a suitable spot and a good quality tree that is right for your climate before you can start.
Getting a Tree
You might be able to find some eucalypti at a local garden center or flower store. The selection is mostly quite limited and for anything special you will either have to grow the them from seed or order from a specialized nursery. Just be sure to not buy a root-bound plant!
When to Plant
In cold climates I find it best to plant in early spring. For me this means April to mid May. In milder climates you can also plant in the fall. The heat of summer and dead of winter should be avoided.
Once you have your tree and a spot that is suited for a eucalypt, dig a wok-shaped hole that is as deep as the root ball of the eucalypt. Remove the eucalypt from its container and put it in the hole. The top of the soil around the hole should be level with the soil around the eucalypt. Fill the hole around the eucalypt with a half-half mix of sand and dirt. In wet climates use more sand in the mix. Now lightly mulch the area around the tree with a large grained mulch, creating a sort of bowl to direct water toward the root ball and leaving some space between the trunk of the tree and the mulch. This will help keep moisture in the soil while the tree establishes itself and protect the roots from frost in cold climates. After mulching give it a good watering.
Watch the tree closely while it establishes and make sure to give it enough water during the hotter parts of the summer. After the first year it should not need to be watered anymore in most climates.
In order to keep a natural flow to my writing; I only reference a source once per paragraph, except when directly quoting someone. This means that if a paragraph contains a reference at the end, any of the information contained in that paragraph might come from the reference. If a reference is before the end of a paragraph then only what has come before the reference in that paragraph contains information from the reference.
Eucalyptus. (2021, May 18) In Wikipedia.
Eucalyptus Growth Rate. (2004, May 24) Barclay, I.
Growing in Containers. (n.d.) Grafton Nursery & Hardy Eucalyptus.
Where to Plant. (n.d.) Grafton Nursery & Hardy Eucalyptus.
Care After Planting. (n.d.) Grafton Nursery & Hardy Eucalyptus.
The following sources proved invaluable in researching the topic and deserve to be mentioned.
The Hardy Eucalyptus Page by
Hardy Eucalyptus by Grafton Nursery & Hardy Eucalyptus.
Planting your eucalypt - Eucalypts for your home garden by Royal Botanic Gardens Victoria.