In this section you will find information on the following topics:-
Once correctly planted, Eucalyptus are relatively easy to look after. A word of warning, they do shed bark and even thought they are evergreen, leaves only last a year or so and then the drop in favour of new leaves being produced. This discarded vegetation makes excellent mulch and does not have to be cleared if it drops on to your borders.
Apart from that, you just need to keep an eye on a few simple things until your new tree is growing away; most importantly watering and weed control.
It is very important to keep an eye on this. Whilst you don’t want the Eucalyptus to become dependent on your watering it every week, you certainly do not want to let a young Eucalyptus wilt. All evergreens (i.e. Shrubs, conifers and trees) are unable to make a good recovery if they are allowed to wilt badly. Deciduous plants have the safety net of being able to drop their leaves and very often revive when water becomes available again.
So water your tree well, if it needs it and especially in a drought or if wilting occurs. This could mean watering once a day on sandy soils to watering once a week. Administer 1-2 gallons of water to your new tree during a prolonged dry spell. In any event, be vigilant over watering until your new tree is established and has grown several feet, which means that its roots are establishing well into the surrounding soil.
We recommend that you seek out a plant food that is going to encourage vigorous root growth and help ripen wood in the Autumn, in preparation for winter.
The fertiliser needs to be high in phosphate and potassium and also contain trace elements, which are vital for balanced growth. A minuscule amount of nitrogen is fine, but excessive nitrogen is to be avoided at all costs: they encourage shoot growth at the expense of root growth and this is a bad thing. Don’t use GroMore. Nitrogen also produces soft sappy growth, which is susceptible to frost damage.
Recommended Plant Feed:
- Chempak No. 8 Low Nitrogen Soluble fertiliser; this is for feeding onions, but is good for Eucalyptus too!
- Granular Bonemeal
What the elements of a fertiliser do for the plant:
Nitrogen (as Ammonia and Nitrates) - encourages fleshy shoots and leaves which is great for lettuce, but disastrous for Eucalyptus. It exacerbates the shoot to root ratio, encouraging instability. Also can increase frost sensitivity. Eucalyptus only require small quantities.
Phosphorous (present as phosphates): this element makes for sturdy beefy growth. Whilst it does not alter root to shoot ratio, it does significantly increase tree girth, root weight and encourages trunk growth. Present in large quantities in Bonemeal.
Potassium (aka Potash): this mineral is involved with the movement of water, nutrients and carbohydrates in the plant tissues. It has many functions, two of the most important (from our point of view) are:
(i) the efficiency of water use and
(ii) how Eucalyptus tolerate and overcome stress brought on by drought, excessively high and low temperatures (winter hardiness) and resistance to pests and diseases.
Good potash levels in August will lead to improved winter hardiness, by helping the tree ripen its wood, in readiness for the onset of Winter.
Being highly soluble, Potassium leaches out from sandy/stoney soils very quickly. Clay soils are more stable and are not likely to be deficient in this important mineral, if their general fertility levels have been maintained.
Trace elements: Molybdenum, Manganese, Calcium, Iron, Magnesium etc. These act in a similar way for the plant as Vitamin tablets do for humans and are important for balanced growth.
(this next bit does appear elsewhere on our website, but it is important and cannot be over-stressed)
About 90% of a Eucalyptus tree’s roots grow in the top 300 - 400 mmof soil, which makes perfect sense when you consider where they come from: a challenging environment where the ability to be the first to access limited rainfall is vital for survival. Eucalyptus are very efficient at taking up water from the soil.
This is why it is immensely important to keep the area underneath your tree absolutely free from weeds and grass (lawn) competition for a minimum of two years after planting; to ensure maximum successful establishment of the young tree.
Grassing down around Eucalyptus in later years can help towards restricting and slowing down growth, but should only be done once the tree is happily established.
A ‘Eucalyptus Lawn’ is a lovely garden feature to walk through.
Keep a 600-1200 mm (2-4 feet) diameter circle around the base of your new tree free of lawn/grass and weeds for at least 2 years, to ensure maximum establishment. Mulch either with a mulch mat or our preference is for 150 mm (6 inches) depth of bark chips, for at least 2 years.
Benefits of mulching:
- Reduces moisture loss, particularly in the summer months
- Keeps nutrients available for longer
- Protects the roots especially in the winter, keeping the soil from freezing.
- Can help prevent weed encroachment
Avoid using compost, manure or anything that composts down quickly, producing nitrogen, as this will not only encourage weeds to grow around the base of the tree, but also result in excessive Eucalyptus top growth.
Herbicide: take care not to get spray drift of herbicides (especially a Glyphosate based herbicide) on to young trees or bark of older trees - it can be fatal.
4. Grazing and stock protection: Livestock, deer and rabbits will eat most Eucalyptus trees so protect young trees with top grade rabbit wire compounds secured in place on timber stakes a good 450 mm radius away from the new tree, if you are concerned. E. subcrenulata has some track record of being unpalatable, but other varieties are likely to be nibbled. We have found that once a rabbit has torn a strip of bark up the length of the Eucalyptus trunk, it does not recover and very often dies.
It is not recommended that you plant Eucalyptus where cattle, sheep, goats and other livestock can eat the leaves, stems or bark. Whilst the species grown in this country are not as toxic as the sugar gum E. cladocalyx, Eucalyptus generally are full of oils and complex compounds and should be treated with caution and respect, particularly around ruminants.
Plastic tree shelters are not recommended, unless they have alot of ventilation holes. Eucalyptus do not become fully dormant; they will grow when the temperature is high enough. In Spring and Autumn, the temperature can fluctuate wildly inside a tree shelter, meaning that on warm days the tree will grow, but young developing shoots will be damaged when there are frosty nights.
In addition, tree shelters can be very humid, leading to disease problems (such as Botrytis mould), unless they are the type that have lots of holes drilled in them.
Use rabbit wire guards to deter deer, rabbits etc. from nibbling your tree.
In their native Australia, there is a whole host of leaf-munching, stem-boring pests and invading fungal diseases all looking forward to making Eucalyptus trees their next meal.
However, generally speaking, Eucalyptus tend not to suffer from many bugs or pathogens in the U.K. Inside a greenhouse, conservatory or polythene tunnel you may get the odd investigative greenfly, but that soon disappears after the first few mouthfuls of Eucalyptus juice. Powdery Mildew can coat the leaves of one or two species (E. neglecta tends to get this a bit indoors), but this too dissipates once the tree is planted outdoors.
The chances of your Eucalyptus contracting something nasty are quite slim, but here are a few to look out for if you are at all worried about the health of your trees:
Silver Leaf Fungus
This disease is the most common Plum tree killer, but silver leaf fungus (Chondrostereum purpureum) will also invade other fruit trees (Apple, Peach), Hawthorn, Laburnum, Poplar, rose, Portuguese Laurel and Eucalyptus.
If your Eucalyptus are growing in an area where the silver leaf fungus is prevalent and you are carrying out a serious amount of pruning on your trees, it is advisable to do the work on a dry day and paint the wounds with a compound such as Medo Pruning Sealant or Arbrex Seal and Heal, to prevent the fungal spores entering the pruning wounds. Sterilise your pruning equipment using a household disinfectant or Armillatox.
N.b. False Silver Leaf is caused by stress induced by drought, malnutrition, sudden unseasonably hot or cold weather or pest attack. It does not result in branch dieback. Improved cultural regime of feeding, mulching and watering will help the plant recover.
Read more about Silver Leaf disease here.
Eucalyptus are also susceptible to the usual tree diseases of Honey Fungus and Phyophthora especially if grown on ground that is poorly drained.
Bacterial canker can invade a damaged stem and cause havoc, as with any woody plant.
Psyllids (Ctenarytaina eucalypti)
Present in the UK since at least 1922, this sap sucker lives entirely on several (but not all) species of Eucalyptus. Eucalyptus parvula, E. subcrenulata and the Snow gums E. pauciflora group are not attacked by psyllids.
Young nymphs and adult psyllids attack the juicy new growths of shoots and leaves (a bit like greenfly). They tend not to be interested in the tough mature foliage. As a consequence, young trees and those being coppiced for foliage production tend to be most at risk of attack. Treatment is worth carrying out using a proprietary systemic insecticide on non-flowering specimens.
For protection, the psyllids encase themselves in a carapace of shed skin and honeydew (delightful!) and because both Eucalyptus and psyllid are not native to the UK, the bugs don’t seem to have any natural predators. Biological control using the imported parasitic wasp (Psyllaephagus pilosus) is sometimes used by commercial growers to control the psyllid pest. This wasp preys exclusively on the psyllids.
Our first piece of advice is ‘Don’t do it’!
Eucalyptus have exceptionally sensitive root systems and if damaged, they go into a monumental sulk.
If the tree is in the wrong place, for whatever reason, you could try moving it provided it has only been growing there for up to two years and no more.
After two growing seasons, it will not transplant successfully; there will be far too much root disturbance. Far better to chop it down and start again with a new specimen planted in the correct place.
Guide to moving a very young tree
Begin in March the year prior to it being moved (yes, we are serious). Draw a circle around the tree, 300 mm away from the trunk. With a very long spade, dig down vertically into the soil, cutting the roots; do this all the way round the tree.
In March of the following year, firstly dig your new planting pit for the tree to be relocated to. Then lift the tree by taking a root ball that is 450 mm radius from the trunk and which should now contain a smaller fibrous root system. At the same time, prune back the tree by 50%, to reduce transpiration loss.
Plant your tree in its new home and keep it well watered for at least six weeks afterwards.
Therefore, from the very beginning, it is far better to choose your Eucalyptus species carefully, matching it to your requirements and growing environment.
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Grafton Nursery, Worcester Road, Grafton Flyford, WR7 4PW
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