Choice of Pot:
The first decision you need to take is whether, long term, you intend to plant your Eucalyptus in the ground, once it has outgrown your pot and/or garden. If, after say 8 years, your tree has grown to 3 – 4 metres (around 10-14ft) tall (species dependent) and is starting to exert its authority, what are you going to do with it? Very few people will take the decision to pot it on and keep it growing, as by this stage it is turning in to a small civil engineering project! If you are going to continue with this impressive behemoth, visit the bottom the page for further guidance.
If you want to give your super-sized tree to a parks department or friend with large garden, you will need to have been growing your Eucalyptus in an air-pot, otherwise you are handing over a liability. Eucalyptus grown in ordinary pots have the wrong root system and when planted out in the ground, they will fall over and squash things like cars and houses.
If you originally purchased from Hardy-Eucalyptus at Grafton Nursery, it will have been grown in an air-pot and have a radial super-fibrous root system.
What does an Air-pot container do? It keeps the root system constantly on its toes. Eucs are a fast growing hardwood and the roots require constant stimulation if they are going to provide you with lots of lush foliage up top. Allow the roots to become moribund and depressed and your Eucalypt will fail to produce the fresh new growth you desire. Its all a question of keeping things growing and in balance. You chop bits off, then feed and water the roots. The roots grow and push out new growth up top, which you can then prune and shape. Its a continual cycle.
To get your own larger air-pot visit our sundries page in the web-shop. A 3 litre air-pot grown Eucalyptus is a good size, big enough to handle with ease and small enough for you to pot on; pot on into a 20 litre for a couple of years and from there into a 45 litre container. A 12 litre multi-stemmed Euc can be comfortably potted on into a 30 litre or 45 litre container.
Round pots and dodgy roots:
If a Eucalyptus is grown in a conventional round pot, the fast growing hardwood root system will encounter the pot wall very quickly and continue to grow round in a spiral (a.k.a become pot-bound). See Air-pots below.
Because of this we advice that you never buy a Eucalyptus that has been grown in a conventional round/square pot or grow bag. Once pot-bound, the roots continue to swell and expand, and if then planted out into the ground they will carry on growing in a spiral. The tree will fail to establish well and will most likely fall over in windy conditions, anything from 1 to 15-20 years later.
Air-pot inside an ornamental container:
Many people become attached to their potted trees and will not want to torch them when they have outstayed their welcome (i.e. outgrown their pot).
To this end, buy it a large air-pot and plant it up correctly. You can always place the air-pot inside another ornamental cover if you do not fancy looking at black spikey containers. See the video on this page. Eucalyptus in metal or blue pots look stunning.
Trees grown in Air-pots do not become ‘bored’. The pot ‘air-prunes’ the roots encourages new roots to grow, and therefore keeps the foliage looking healthy.
Provided there is an air gap to allow air-flow between the air-pot and your pot cover, root pruning will continue and your Eucalyptus will remain active. At a later date (say in 5-8 years time) and if the need arises, you can donate your magnificent specimen to be planted out in a garden, with confidence.
If you feel no allegiance to your Eucalyptus, grow it in a large conventional ornamental terrace pot, but be prepared to dispose of it if it grows too large. In this instance, please do not be tempted to plant it in the ground: it seriously is a liability.
Please ensure your Eucalyptus container (whatever the choice and style) is sat squarely over a flagstone. Eucs produce prospecting roots, which can grow through the bottom of a pot and into neighbouring soil.
Compost
The compost needs to be stable, long-lasting, free draining and moisture retentive. To make your life easy in the long term and to keep your Euc happy, make your own by blending John Innes number 1 or 2 with a good quality peat free compost (Ericaceous is best) on a 50:50 basis. Remove any large lumps which could block the holes in your Air-pot container. Add a pinch only of moisture retaining granules (hanging basket ‘swell-gel’) to help with the watering and some low nitrogen, slow release fertiliser granules (quantity as per the manufacturer’s recommendations).
Aftercare
Feeding
Why bother feeding? To keep your Eucalyptus bushy and well behaved, you will be needing to prune it at least once a year. This involves the removal of vegetation and therefore stored carbohydrate. Removing this valuable resource from your tree and not replacing it with plant food will mean that your tree will become depressed and completely fail to produce new shoots; it will starve to death.
If you used slow release fertiliser granules to pot on your Eucalyptus, they will keep working for one growing season. Thereafter, you will need to liquid feed or insert slow-release-granule plugs in the following April.
Liquid feed your potted Eucalyptus once a week, from the beginning of April until the end of August, using a low nitrogen, low phosphorous, high potash fertiliser (Chempak No.4 soluble powder). If pruning on a regular basis, you will also need to apply organic slow release sulphur chips once a year in the Spring. Dose as per manufacturers recommendations. Sulphur is the building block of proteins and helps ‘build tree’. It is as essential as Nitrogen, Phosphorus and Potassium, but absent from many general plant foods.
Food note: In any event, liquid feed your Eucalyptus twice during August with a high potassium feed to ripen the wood and increase your trees ability to deal with cold weather and frost conditions. This applies to any potted plant, not just Eucalyptus.
Watering
Keep an eye on the watering of your potted Eucalyptus. Whilst they are drought tolerant when established and growing in the ground and they can tolerate a little drying out in the pot, but they are fairly unforgiving if you let them become brown and crispy…not even Mary Berry will be impressed. Shrivelled leaves do not recover and once the plant gets to the permanent wilting point there is a high possibility it might die.
Airpots can dry out quite quickly in windy weather and therefore a little moisture retaining granules can help with compost water retention and reduce stress for your tree (but don’t be tempted to over do it). Nor should you ever leave your tree sitting fully submerged in water to soak for more than half an hour; it is possible to drown roots. They are not aquatic!
Water note
To help give you an idea of the correct weight of a fully hydrated air-pot grown Eucalyptus during the growing season, as a rule of thumb:
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1 litre air-pot, when wet, equates to a large mug of tea.
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9 litre airpot, when wet, equates to an average full carrier bag of supermarket shopping.
Any lighter than this and they will most likely need watering.
In the nursery, we water every day from May through to September, even if it rains.
Rain is a waste of time for shrubs in pots; it only washes the leaves. If it does soak into the compost, it likely only hydrates the first few centimeters – tricking you into thinking to rest of the compost is wet further down – and also dries out more quickly than tap water.
Watering over winter: keep just moist, never allow to dry out. Check once a week and water according to need.
Pruning
A little trimming now and then will keep your potted Eucalyptus happy and in good condition. Generally most species are fast growing and they can produce a great deal of top growth, which will be out of balance with the roots.
You can nip out the ends of the shoots on a regular basis during the growing season, especially with the bushier species. Also, depending upon your choice of species and style of tree (either bushy shrub or shrub-on-a-stick standard), prune in the spring as growth starts.
See our training and pruning advice page for more information.
Depending on how vigorous or not the species, you may only have to prune once a year, but carry this out between March 18th and end of June. Never during the winter.
Winter Protection
Any potted plant left out of doors over winter will be at risk when the temperature drops to 0°C, particularly for prolonged periods. The compost in the pot freezes and root death occurs below -4°C. Eucalyptus especially do not thrive under such conditions.
All potted Eucalyptus are more vulnerable to freezing weather and frosts than the same species when grown in the ground. Suggestions on how to protect the roots:
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Move the Eucalyptus to a more sheltered location and either wrap the pot in hessian sacking stuffed with straw or stand the Eucalyptus pot in a larger pot packed with straw.
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Move the plant to a well ventilated greenhouse. If this is frost protected, your tree will be fine, otherwise it may still be a good idea to wrap the pot in straw
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Move the plant to a light and airy well ventilated conservatory for the hardest part of the winter.
If you are growing one of the more tender species of Eucalyptus such as E. deglupta, E. macrocarpa, E. citriodora, E risdonii (and you don’t live in Cornwall), you will need to overwinter them in well-ventilated, well-lit frost-free conditions – this means a temperature that never falls below 0°C
Avoid keeping your potted Eucalyptus anywhere warm and/or dark over winter, as it will not be happy.
Choice of species
I have left the choice of species until last, because if you would like to base your choice of tree on your own knowledge, then you need to have worked through all the other parameters in the list above. As is always the case with any tree; it is important to match the right tree to your environment, to ensure that it is going to be successful and give you the desired result.
i) You can grow any Eucalyptus species in an Air- pot. How long you keep it for and the size it will ultimately attain, depends very much on the species, its growing conditions and how you look after it in terms of food, water, micro-climate and sunlight.
ii) Short term: 1 to 2 years, as an ‘extended bedding plant’ E. globulus bicostata has stunning foliage and white stems, grows very fast, but probably only hardy down to -4 Celsius in a pot. We can achieve a tree 4m tall in one growing season with this species, when hooked up to the automatic irrigation system.
iii) Up to 6-8 years: Bushy species are the best choice for pot culture. Have a look at the following:
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E. ‘Azura’ is a brilliant new cultivar and one of our favourites, slower growing, more compact habit. Can be trained as either bushy shrub or standard. Azura can easily get to 8-10 feet as a pot grown specimen
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E. ‘French Blue’ (France Bleu): another cracking good cultivar to emerge from France. Compact, naturally incredibly bushy; can be kept anywhere from 1m (3ft) with annual pruning, up to 3m (10ft) depending on how much space, food and water you give it. Quite slow for a Euc., but great in a patio pot.
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E. pauciflora subsp. niphophila ‘Mount Bogong’ makes a terrific container subject with very interesting bark with winter interest. Take a 3 litre, pot on into a 20 litre (keep it pruned) and from there, into a 45 litre container.
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E. pauciflora subsp pauciflora ‘Buffalo’ is a very rare, beautiful dwarf snow gum, which we grow exclusively as a multi-stemmed specimen. Excellent white bark detail as it matures. Truly impressive when grown in a 30 litre container or larger.
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E. archeri, E. coccifera, E. crenulata, E. nicholii, E. parvula: Grow as multi-stemmed specimens and keep the leading shoots pruned and in balance with the rest of the shoots. Don’t allow one shoot to dominate or else it will grow into a tree. E. parvula is fabulous as a multi-stemmed shrub and matures into the most amazing small tree if allowed to grow on in a larger pot, with a super umbrella-like canopy – see photo on main species data sheet. E. coccifera does best when grown on in larger planters and containers and kept well watered. E crenulata enjoys a warm sunny position and needs shelter from cold exposed conditions.
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E. pulverulenta ‘Baby Blue’: although traditionally grown as a tall bush in the ground, Baby Blue can be persuaded to grow as a standard. It requires pruning in March to keep a compact head . See the main data sheet for further information
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E. risdonii has a wonderful aroma and very silvery foliage, but will need winter protection in most parts of the UK; it will probably overwinter outdoors in Cornwall. Grow as multi-stemmed specimens and keep the leading shoots pruned and in balance with the rest of the shoots. Avoid only one or two shoots from dominating, otherwise your pot specimen will grow into a tree
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E. kybeanensis: pot on slowly by degrees. This finely rooted Euc does not like being over potted. Establish a good root system with balanced top growth, by pruning back the leading shoots every March and again in June. Take a 3 litre specimen plant and pot on into a 12 litre air-pot for a couple of years. Eventually pot on into a 30 litre air-pot.
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E vernicosa is good provided you have it hooked up to an automatic drip irrigation system. Never allow it to dry out in a pot, because it will become very sad. It grows very well for us at the nursery, on the drip irrigation. Great small bushy evergreen tree in the garden, planted in the ground, if you have slightly swampy soil.
Click here to see our collection of trees suitable for growing in containers.
iv) Longer than 8 years: choose the smaller species as detailed above, they grow more slowly. Growing as multi-stemmed specimens makes for a better result; a more stable tree with a rewarding amount of foliage. Remember to pot on regularly, feed and water.
Eucs don’t really get vine-weevil, but as your trees mature, it would be good practice to apply nematodes at the right time of year, just in case any adventurous weevil has taken up residence. Google search for ‘Nemasys’.
Growing a super-sized Eucalyptus Tree: notes to follow very soon… not enough hours in the day.
