Eucalyptus gunnii 'Silver Drop'

Eucalyptus gunnii 'Silver Drop' is a wonderful fragrant foliage plant that is in high demand in the cut flower trade. Bred especially to provide small, round silver-blue-green leaves 'Silver Drop' is better for fine floral work. Use it as filler in mixed bouquets where the silvery blue-green leaves appear to be strung on stems, add interesting colour, texture and aroma.
With fast growth it is ideal for both year round greenhouse and outdoor field production and is popular in both the fresh and dried cut flower markets. A dwarf improved version of 'Silver Dollar' providing superb quality cut foliage which is an ideal filler.

The magnificent Eucalyptus gunnii is one of the most popular hardy varieties of eucalyptus which thrives in our climate. It bears silvery-blue, rounded young leaves that once mature, give way to long, glaucous, sickle-shaped adult foliage. 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. The smooth whitish-green bark is shed annually in late summer to reveal greyish-green bark, sometimes flushed pink or orange. Although not often seen, it can bear beautiful creamy-white blooms when it does flower in summer.
This magnificent evergreen, is known to be one of the fastest-growing and hardiest of Eucalyptus varieties. It can grow up to 1m (39in) in the first year and once established is very hardy, tolerating down to -14°C (7°F) on a regular basis and down to -20°C (-4°F) for brief periods. Easy to care for, it requires minimum attention.

• Awarded the RHS Award of Garden Merit
  Eucalyptus gunnii was awarded the Royal Horticultural Society’s Award of Garden Merit (AGM) in 1993.

Sowing: Sow at any time of year.
Seeds germinate at temperatures of about 18 to 24°C (65 to 75°F), they can be slow to germinate, usually taking place between two and five weeks. Patience may be required as they may take much longer dependent on temperatures and the time of year.
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.
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.

Cultivation:
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.

Planting Outdoors:
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.

Container Specimens:
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.
It is possible to grow a eucalyptus indoors, given enough light. They like to summer outdoors, where their fragrant half-moon-shaped leaves rustle in the breeze. Because they grow rapidly, pruning can help contain them…at least for a while.

Pruning:
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.

Foliage for Cutting:
Wait until the tips mature to avoid wilting. Eucalyptus is generally at its best late summer into autumn and winter. Harvest stems and condition by place straight into buckets of water leaving to rest preferably overnight.
The colour of the foliage is due to a grey waxy bloom on the leaf, this can be quite fragile and easily rubbed off. Care must be taken in harvesting and handling the foliage. They are best transported as bunches in cellophane sleeves. Normal cut flower post-harvest principles of low storage temperature with higher humidity are also suitable for Eucalyptus foliage.
The foliage lasts well out of water, the stems have astonishing vase life and may also be dried for extended use.

Plant uses:
Containers, Flower Arranging, Architectural, Sub-Tropical, Foliage Specimen, Insecticide, Homemade Soap, Natural Dye.

Other Uses:
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.

Origin:
Eucalyptus gunnii is a threatened species of Eucalyptus that is endemic to a small area of frost hollows in 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.

Nomenclature:
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).
Early settlers used the sap to make an alcoholic drink by cutting into the trunk and collecting the sap, which is similar to Maple syrup, the sap was used as syrup or once bottled and capped it fermented and produced a drink similar to cider, from which they get their common name of Cider Gum.

Foliage Production:
Eucalypts for foliage production are often grown in Mediterranean climates and generally grow well as long as there are no very cold winters, no late frosts which may burn new growth in spring, or excessively hot summer conditions. Windbreak protection may be required depending on the growing site, as too much wind may cause excessive rubbing of the branches and leaves damaging the grey wax on the leaf surface, or causing the breaking of branches.
The change in the plant from juvenile to mature foliage is a problem because the foliage is usually not as attractive. This can be controlled by pruning which will stimulate new juvenile growth. This new growth will be more susceptible to frost at first, so consideration should be given to the likelihood of frost when pruning.
Pruning of the trees after planting and allowing for establishment is generally started following the second year growing season, after the winter period, pruning to a height of about 1.2m (4ft). This has been found to produce the most foliage as it enables the formation of a branching framework of 2 to 3 stems, which is most suitable for future maintenance and harvesting. More severe pruning may cause stunting or even tree death, and should also be avoided with subsequent yearly pruning.
Some variation in leaf colour has been observed, with leaves being slightly darker on the sunward side, and some new growth may have a purple shade that disappears with age.