The magnificent Eucalyptus gunnii is one of the most popular hardy varieties of eucalyptus, which thrives in our climate. With silvery-blue, rounded young leaves that give way to long, glaucous, sickle-shaped adult foliage and smooth whitish-green bark that is shed annually in late summer to reveal greyish-green bark, sometimes flushed pink or orange. Although not often seen in the UK, it can bear beautiful creamy-white blooms when it flowers in summer.
Eucalyptus are naturally trees, sometimes reaching a great height, but in gardens regular firm annual pruning can keep them as large shrubs and maintain a supply of the juvenile foliage enjoyed by gardeners and flower arrangers. Ideal in a pot on the patio, it can be grown to form a standard tree and clipped regularly for a compact head of silver-blue foliage which produce a scented natural oil that will keep bugs and gnats at bay.
This magnificent evergreen, fast growing specimen can grow up to 1m (36in) in the first year and once established, are hardy to -18°C (0°F). Easy to care for, it requires minimum attention.
Eucalyptus gunnii was awarded the prestigious RHS Award of Garden Merit (AGM) in 1993.
Sowing: Sow in spring to early summer.
Seeds germinate at temperatures of about 18 to 24°C (65 to 75°F). Germination can take place in a few weeks, but as much as several months may be required.
A practice many growers use is to sow seed directly into containers 20 to 30cm (8 to 12in) deep to allow for the eventual, vigorous root system. Eucalyptus resent root disturbance, this practice eliminates the need to transplant into pots after the first true leaves have formed. Other propagators stratify seeds in plastic bags and plant them in pots after germination.
Place the seeds in a polythene bag containing a moist, sterile medium such as peat or grit, seal and label and put in the refrigerator at about 4°C (39°F). Leave for about two months, check regularly and plant as they germinate.
Sowing into containers:
Sow seeds about 1.3cm (0.5in) deep into pots containing a moist, well drained and sterile compost. (John Innes or 50% multi-purpose and 50% perlite or coarse grit.). Cover with sieved compost or vermiculite. Provide bottom heat if possible. and cover pots with plastic or glass to retain moisture and humidity and protect the seed. Keep moist at all times.
When large enough to handle, transplant/prick out each seedling in its own pot of multi-purpose compost. Seedlings in shallow seed trays need transplanting promptly, handling them carefully by holding the seed leaves, rather than the emerging true adult leaves. Seedlings in root trainers can be left a little longer before transplanting, allowing their roots to fill the module, and then transplanting the whole plug of roots and compost in one go.
Water regularly, as needed, and feed with liquid fertiliser every month, growing the seedlings on into small plants. The following spring or summer, when the plants are more robust, harden off for 10-14 days before planting out.
Plant them out into the garden in late summer to early autumn, giving them the winter to settle their roots into the soil before coming into active growth the following spring. Best grown in sunny sheltered spots. Cold winds are more injurious than frost.
Water pot thoroughly and allow to drain. If planting in a lawn, remove a circle of turf 60cm (24in) across. Dig a hole twice the size of the pot and fork over the base, incorporating a handful of general fertiliser and a bucketful of planting compost. Drive in a tree stake a little off-centre. Remove the pot and tease out any matted roots. Position the tree against stake with top of root ball level with surrounding soil. Replace remaining soil, firming-in well. Secure tree to stake with adjustable strap. Water thoroughly, then once a week during the first growing season and during dry spells while the tree is establishing. Garden-grown specimens should not require regular feeding.
Grow in any good multi-purpose potting media or soil-based ones such as John Innes No 2 or No 3. Adding up to 30 percent by volume of coarse grit is often helpful. They benefit from monthly feeding with a balanced liquid fertiliser. Keep the compost moist during the growing season and reduce watering in winter. Repot every two years.
Eucalyptus require minimal pruning if grown as a tree, removing any broken, diseased or crossing branches in late autumn or winter. For the best juvenile foliage, prune in early spring cutting back the stems to two or three buds above the base.
It may be maintained as a shrub, with juvenile foliage by stooling or pollarding it in late winter.
Containers, Flower Arranging, Architectural, Sub-Tropical, Foliage Specimen.
When crushed, the leaves produce a scented natural oil which is often used for cleaning and as a natural insecticide. Natural dyes from the leaves & bark can give pretty colours, usually ranging from tan and yellow through to rust and red. It is also used for producing paper.
Eucalyptus gunnii is a species of Eucalyptus endemic to Tasmania, Australia, occurring on the plains and slopes of the central plateau to around 1100 metres.
It is a diverse genus of trees (and a few shrubs), the members of which dominate the tree flora of Australia.
There are more than seven hundred species of Eucalyptus, mostly native to Australia, with a very small number found in adjacent parts of New Guinea and Indonesia and one as far north as the Philippines islands.
The genus name Eucalyptus is from the Greek eu, meaning 'good or well', and kalyptos, meaning 'covered', referring to the calyx which forms a lid over the flowers when in bud.
The species name 'gunnii' after Ronald Campbell Gunn FRS, (1808-1881). Gunn was a first-rate botanist and general scientist, born in South-Africa he arrived in Tasmania, Australia in 1830. His interest in botany was ignited by his friendship with RW Lawrence of Launceston, who corresponded with the great British botanist WJ Hooker.
Gunn became a passionate biologist and travelled extensively, dedicating himself to collecting, recording and forwarding specimens of Tasmanian flora and fauna to Hooker. He also established a private botanic garden in Glen Dhu, Launceston. His contribution to botany is commemorated in Joseph Hooker's introduction to Flora Tasmaniae (1860). Originally over fifty species of Tasmanian plants contained Gunn's name. In 1854 Gunn became the first Tasmanian to be elected a Fellow of the Royal Society of London.
Sir William Jackson Hooker, who dedicated his Flora Tasmaniae to Gunn, and another Tasmanian botanist, William Archer, speaking of Gunn in his Introductory Essay said:
‘There are few Tasmanian plants that Mr Gunn has not seen alive, noted their habits in a living state, and collected large suites of specimens with singular tact and judgment. These have all been transmitted to England, accompanied with notes that display remarkable powers of observation, and a facility for seizing important characters in the physiognomy of plants, such as few experienced botanists possess’.
Many Eucalyptus, but far from all, are known as gum trees in reference to the habit of many species to exude copious sap from any break in the bark (e.g. Scribbly Gum).
- Additional Information
Average Seed Count 30 Seeds Family Myrtaceae Genus Eucalyptus Species gunnii Common Name Cider Gum, Gum Tree Flowers White to cream, (not often seen in the UK) Natural Flower Time July to October. Foliage Fragrant, elliptic, grey-green horizontal branches Height 15-20m (15-20ft) if unpruned in 15-20 years. Broadly conical. Spread 8-12m (12-15ft) if unpruned in 15-20 years Position Full sun to part shade Soil Prefers neutral to slightly acidic soil that doesn't dry out