Eucalyptus viminalis is an incredibly useful native tree, and well worth getting to know. For any Australian gardener living with cooler, wetter conditions, it is the perfect tree to add drama, whether you’re planning on coppicing it into a shorter shrub or hedge, or leaving it to grow to its ultimate, and dramatic height.
In this guide, we’ll look at some of the practical concerns around growing Eucalyptus viminalis at home, as well as some useful hints and tips for propagating and caring from this moisture-loving tree, often called the Tasmanian white gum.
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Family: | Myrtaceae |
|---|---|
Genus: | Eucalyptus |
Species: | E. viminalis |
Common names: | Tasmanian white gum, manna gum, ribbon gum |
Origin: | Australia |
Location: | Outdoor |
Type: | Tree |
Growth: | Up to 90m tall |
Sun requirements: | Full sun |
Foliage colour: | Green |
Flower colour: | White |
Flowering: | Summer and autumn |
Edible parts: | Sweet manna (crystalised sap) |
Maintenance level: | Low |
Poisonous for pets: | Toxic to cats and dogs |
What is Eucalyptus viminalis?
Eucalyptus viminalis is perhaps best known as the manna gum, but other common names include Tasmanian white gum (due to its habitat), ribbon gum (due, both, to its bark and its slender leaves) and simply white gum.
The rough, peeling bark of the lower section of the tree is only found on mature specimens, and the higher parts of the tree are impeccably smooth, covered in an even white bark.
It should be noted that Eucalyptus viminalis can reach heights of up to 90m, but rarely does. In nearly all cultivated settings, in open space, these trees grow to around 30m tall, occasionally reaching 50m.
However, that shouldn’t put passionate gardeners off, as it is easily coppiced to form a feathery hedge or statement shrub.
What is Manna Gum’s Natural Habitat?
Eucalyptus viminalis is native to Australia, and specifically found in the southwest, primarily in coastal regions. Its common name, Tasmanian White Gum, gives plenty of clues to its preferred conditions, but it can cope with drier summers and milder winters.
If you are hoping to match your garden soil to its natural range, aim for moisture-retentive but draining conditions, and as trees mature, don’t be afraid to underplant them with moisture-loving and hungry natives.
Occasionally coppiced E. viminalis offers a wonderful white backdrop to colourful flowering plants.
Common Uses for Eucalyptus viminalis
Eucalyptus viminalis has countless uses but it is, more often than not, planted as an ornamental native. Its most famous trait is the gum which exudes from the bark, called manna. The gum crystalises behind the bark and can be extracted, or collected from around the base of the tree and used as a sweet sugar substitute.
Like all Eucalyptus trees, manna gum should never be consumed in large quantities, and even the edible manna has laxative qualities, so eat it as a treat, not a dietary staple.
Eucalyptus viminalis Subspecies
Eucalyptus viminalis is generally hard to get hold of, and not a commonly grown garden tree but, if you can find one, be sure you know the subspecies’ particulars, as there is some variation in their growing habits and leaf forms that will make a big difference to its eventual effect.
In terms of foraging and sourcing manna gum out in nature, all five of these subspecies have edible gum, which is identified as crystalised white, pea-sized, pieces.
Find the gum hidden behind the peeling bark in lower sections of the tree or from damaged bark.
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Source: Reforest Bush Nursery
1. Eucalyptus viminalis subsp. cygnetensis
The easiest subspecies of Eucalyptus viminalis to identify is usually E. viminalis subsp. cygnetensis. This is thanks to the higher occurrence of rough bark, which can extend up to its lower limbs, unlike other subspecies, where the rough bark tends to be restricted to the lower half of the main trunk.
Cygnetensis has a wide native range, from the Grampians to Kangaroo Island.
2. Eucalyptus viminalis subsp. hentyensis
E. viminalis subsp. hentyensis is endemic to Tasmania. The rough section of bark is very restricted, usually to the very base of the trunk, and it will grow on much poorer soil than other subspecies, often found in free-draining poor sands.
Young leaves are broader but develop into the typical lanceolate leaves of other subspecies through the year.
3. Eucalyptus viminalis subsp. pryoriana
The smallest of the subspecies, growing to just 15m, is E. viminalis subsp. pryoriana. The trunk is usually covered in rough bark, with smooth limbs beyond it. It can be found growing in similar conditions to hentyensis, on poor coastal sands.
E. viminalis subsp. pryoriana is endemic to Victoria, growing along the southern coast to the east of Melbourne.
4. Eucalyptus viminalis subsp. siliceana
A newly identified subspecies, E. viminalis subsp. siliceana, was noted in 2011 growing in the Wail State Forest in Victoria. It is largely similar to E. viminalis, but has distinctly glaucous new growth, which fades to green as leaves develop.
5. Eucalyptus viminalis subsp. viminalis
The most common subspecies of E. viminalis is subsp. viminalis, which is found growing throughout New South Wales, Victoria, Tasmania, Bass Strait Island, and southern parts of South Australia.
It prefers wet conditions, so is often found alongside streams, and will cope well with a variety of soil conditions provided it has good irrigation.
How to Grow Eucalyptus viminalis
Growing Eucalyptus viminalis is actually pretty straightforward, but it is worth noting that it isn’t as drought-tolerant as other Eucalypts. Its ideal conditions are well-drained soils with high rainfall or even streamside locations.
When it comes to the practicalities of growing manna gum, there are some other very key considerations to make, such as height and habit.
These trees are recorded as reaching 90m tall in parts of Tasmania and are capable of that in gardens in exceptional circumstances, so they are not suitable for planting near houses, or anywhere where they will overhang structures unless treated as coppiced hedges, or pruned regularly to maintain them as a shrub.
Below, we’ll look at everything these trees need, from starting seeds to caring for mature specimens and even taking care of pest problems.
Source: Trees On The Tablelands
Ideal Conditions for Growing Eucalyptus viminalis
Soils and light conditions can vary slightly when planting Eucalyptus viminalis, but it does like a lot of transient moisture, and plenty of light if you can give it.
Soil & Drainage
Aim for relatively poor soil that can hold some moisture, without becoming completely waterlogged. Eucalyptus viminalis does grow in boggy conditions but prefers a steady supply of draining water.
In South Eastern Australia, finding the right soil for E. viminalis is usually simple, but in new build properties, with heavily disturbed gardens, and in previously cultivated landscapes, it can be tricky to regain the right soil balance.
As a bare minimum, make sure your trees are given reasonably well-drained soil, and avoid working in compost or soil improvers.
Light & Temperature
Eucalyptus viminalis can be found growing in woodlands and out in the open. Young trees will develop in part shade or full sun, and coppiced plants can be grown in any light conditions other than full shade.
Shelter
No shelter from wind or ocean winds is required. Eucalyptus viminalis can grow in coastal conditions and copes well with high winds. Young trees, as always, should be staked for their first few years to prevent excessive rocking while the roots establish.
Planting Eucalyptus viminalis
If you have a young Eucalyptus viminalis sapling, or small tree ready to plant in the garden, it is worth doing a little bit of soil preparation to help it get established, but that doesn’t mean feeding, or adding manure, as many young trees prefer.
Instead, dig a hole large enough to accommodate the root ball (a little wider if the soil is heavy or compacted), and fork the base of the hole loose. Position your Tasmanian white gum with its best face forwards, and then fill back in with the same soil.
To boost rooting, add mycorrhizal fungi to the planting hole, or rub directly on the root ball before backfilling with soil.
Once planted, add a tree stake, tied loosely to the tree, and pointed into the prevailing wind. This isn’t 100% necessary, but it will help the roots to establish without disturbance and can be removed after two or three years.
How to Propagate Eucalyptus viminalis
There is no perfect way to propagate Eucalyptus viminalis at home, as cuttings and seed propagation both have pitfalls. In commercial nurseries, cuttings are grafted onto rootstock grown from seed to provide the most reliable results.
Manna gum has a habit of cross-breeding, so its seeds are rarely true to their parent, but they do, and will, germinate reliably even in unfavourable conditions.
Cuttings from all types of eucalyptus are unreliable and require special treatment to root well.
If you have a successfully germinated eucalyptus rootstock, from Eucalyptus viminalis, it can be used to graft a young cutting onto. This is the most reliable method of producing the same species or subspecies of E. viminalis.
How to Care for Tasmanian White Gum
After a couple of years in your garden, the roots of Eucalyptus viminalis will have thoroughly established, eventually reaching as far out into the earth as the tree is tall. When roots are well developed your tree shouldn’t rock in the soil at all, even when knocked.
At this point, you can remove any stakes or supports that were in place, and focus on caring for your manna gum as though it was a fully mature 50m tall tree. In short, that means doing very little.
Pruning Eucalyptus viminalis
Eucalyptus viminalis doesn’t need pruning if you are growing it as a full-sized tree, but pruning is essential in smaller gardens to stop it from becoming overwhelmingly tall. Just like any mature tree, E. viminalis should be pruned carefully and if in doubt, use a qualified tree surgeon for more extreme cuts or branch removals.
If you are routinely removing smaller limbs, make an initial cut underneath the branch to 1/3 of its width, and then cut down from the top. This prevents tearing and snapping, and offers a cleaner cut, meaning the tree will heal faster, and with less chance of infection.
When to coppice Eucalyptus viminalis
If your E. viminalis is planted as a shrub or hedgerow, it will need regular coppicing. If it has missed a few years of this treatment, it’s quite simple to get it back into shape too.
After flowering, cut back hard to the same point each year. This can be done by alternately pruning half of the new growth each year, so that there is always some structure, or you can get more dramatic structure by cutting the entire plant back to the coppice point every year.
Watering & Feeding
A full-sized E. viminalis can drink several bath-tubs-worth of water per day, drawing moisture in from 100 square feet or more of earth. Even in droughts, these moisture-loving plants can survive once they are truly established in their landscape.
However, cultivated manna gum, especially shrub-pruned or coppiced specimens will require more irrigation if you live outside of their native range (southeastern Australia).
Water coppiced manna gum if it doesn’t rain for more than a fortnight in summer, with at least a bucket per plant. Never water if the soil is still moist.
Common Manna Gum Pests and Diseases
Eucalypts are rightly known as pest-proof plants, but apparently, that reputation has escaped some intrepid insects that still seem determined to make these trees their home.
Gall wasps and eucalyptus leaf beetles are common, as well as the problematic emperor gum moth. The pests are no trouble for mature plants, but defoliate and spread fungal problems that are hard for young plants or coppiced cultivars to recover from.
Below, we’ve got a quick guide to spotting and dealing with each, followed by some helpful information on the fungal and bacterial problems often associated with them.
Emperor Gum Moth
The emperor gum moth is one of a few moth species that has adapted to rely on the sweet sugary leaves of eucalyptus. Its caterpillars can defoliate young trees in a matter of days, but in reality, it is of no threat to the wider environment and poses no risk to mature eucalyptus trees.
If you see the caterpillars on young trees, pick them off routinely before they become a major problem.
Gall wasps
Gall wasps, like gum moths, are specially adapted to the conditions provided by eucalyptus leaves. Their eggs are laid inside leaves, and larvae develop inside galls between the outer layers of the leaf.
They spread fungal infections, as well as causing defoliation and discolouring leaves. This is because the larvae take nutrients from inside the leaf before it as a chance to benefit the leaf.
Usually, this will cause defoliation on heavily infested trees. Leaves with galls should be removed and destroyed to slow the spread of the problem and limit recurrence.
Eucalyptus Leaf Beetles
Eucalyptus leaf beetles are native pests with rounded, usually satin-brown or grey, shells. They lay eggs on E. viminalis leaves, and their young feed until their nursery leaf is done with, before moving on to the next.
They are well controlled by garden birds, and should not be killed with insecticides, which have an adverse effect on other wildlife. Instead, pick off the beetles as you see them, and check leaves for eggs if there is any sign of damage. Place eggs and beetles on the bird table as a treat for your more welcome garden visitors.
Common fungal problems, like Phytophthora, Pythium, Verticillium and Botrytis all adversely affect Tasmanian white gum (E. viminalis), and all have similar symptoms depending on the part of the plant they take hold of (leaf discolouration such mouldy or brown, dry, lesions on leaves, and crown or root rot causing anaemic, yellowing and dropping leaves).
But as well as the common issues, there are some quite specific things to look out for that are particularly problematic on E. viminalis.
Powdery mildew
Despite loving moisture-rich environments with heavy rainfall and mild winters, E. viminalis is susceptible to powdery mildew. It isn’t worth worrying about on mature trees but can have severely adverse effects on young trees.
When you notice a powdery coating across manna gum leaves, there are several ways to help the plant to heal itself, before attempting chemical or even organic anti-fungal sprays.
Start by reducing watering, and thinning the canopy to improve ventilation. Check that the soil is draining properly to avoid overly boggy conditions.
I know it’s counter productive for a tree that loves moisture, but standing water and regular rainfall are quite different. Always avoid standing water with any Eucalyptus species. Powdery mildew can be treated with organic fungicides as a last resort.
Cinnamon fungus
Cinnamon fungus doesn't just attack E. viminalis, it is a widespread mould, called Phytophthora cinnamomi. The mould can pass between plants on clothing, animals, dirty tools, rain splashing, or just water draining from one part of the garden to the next, so it is important to remove any sign of it as soon as possible.
I have never heard of it significantly affecting mature trees, but it can cause devastation on coppiced eucalyptus or young manna gums.
Signs are sudden dieback of foliage and young branches, and a soft, mushy crown. If this happens, dig up the plant, and a few feet of soil around it. Replace that with gritty, well-drained compost and avoid planting in that spot for a few years.
There is little you can do to avoid Cinnamon fungus on manna gum, simply because their preferred conditions are the same.
Eucalyptus viminalis Frequently Asked Questions
Source: Trees and Shrubs Online
How tall does Eucalyptus viminalis get?
Eucalyptus viminalis generally grows to 30-50m in height, but there are some specimens growing in Tasmania that are recorded at 90m tall, and as we know from discoveries as recent as 2011, there are subspecies yet to be found.
What is Eucalyptus viminalis used for?
Eucalyptus viminalis is most commonly used as a fast-burning firewood and craft timber, but it has several antiviral and anti-inflammatory uses, as well as a delicious sweet manna that can be harvested from behind the bark.
How do you identify Eucalyptus viminalis?
Eucalyptus viminalis can be identified by its lanceolate foliage, darkening to green as leaves mature, and rough bark on the lower portion of the trunk, changing suddenly to smooth white bark further up. Flower buds and seed pods are nearly always found in clusters of 3 or 7.
Is Eucalyptus viminalis evergreen?
Eucalyptus viminalis is an evergreen tree, growing to 90m tall in its native habitat, and up to 50m in cultivation. Its evergreen foliage makes it a great selection for coppiced hedging.
How hardy is Eucalyptus viminalis?
Eucalyptus viminalis is hardy down to -16°C making it one of the most cold-hardy native trees in Australia.
How often does Eucalyptus viminalis shed bark?
Eucalyptus trees shed their bark almost constantly throughout their life. They are evergreen trees, with annual growth cycles though, so the most prolific bark shedding happens in spring and summer before and during flowering.
How long does a Eucalyptus viminalis tree last?
Eucalyptus viminalis is a long-lived tree, with some specimens in the wild dating well over 200 years.
What is the meaning of Viminalis?
The Latin word ‘viminales’ means “feminine”, but it is more likely to be a translation of ‘vimin ales’, meaning wicker wings – perhaps due to the ribboning bark which is useful for strapping, or the flexible young stems.
Grow Eucalyptus viminalis for a Graceful Addition to Your Garden Landscape
Eucalyptus viminalis is one of Australia’s most useful trees, but it is also one of our least known. It is not commonly regarded as invasive, and its desire for cooler, wetter conditions limits its spread outside of its native range, making it a fairly easy tree to control.
While Eucalyptus viminalis can become overwhelmingly large, some thoughtful pruning and careful planning will provide you with a gorgeously graceful tree, with tons of character that is quite unlike anything else in its genus.
Published on February 10, 2024 by Nathan Schwartz
Last Updated on September 19, 2024
