Cider Gum Tree/Eucalyptus Gunnii
The juvenile foliage of this Tasmanian tree is so good for floral work, that Eucalyptus gunnii is worth growing even in the restricted confines of a pot on the patio. In its native habitat, the Cider Gum can grow to 30m (100ft), when it will develop the distinctive creamy, pinky-brown peeling bark; if left to grow as a tree, the pretty juvenile leaves are gradually replaced by the sickle-shaped, rather uninteresting sage green leaves of the adult plant. Although container-grown plants are restrained by both annual pruning and pot culture, they can still put on about 1.5m (5ft) of growth a year. The Cider Gum is also a good shrub for the border beside a terrace, where it will benefit from a roomy root-run in enriched; plant small specimens directly into garden borders for the best chance of a well-established root system, as Gums suffer from wind rock. To retain the silver-blue, circular leaves of youth, the plant must be chopped back hard (to as little as 25cm/10in) at least every other year, as soon as all danger of frost has passed. Once the new growth appears, select the best 3-5 shoots and thin out the remainder.
Grow this plant where the long shoots will not be buffeted by cold winds: although tolerant of temperatures to -5°C (23°F), the Cider Gum will fail if blasted by chill winds. The leaves, too, will suffer and become shredded. In Summer, this plant will withstand warmth as long as the rootball is moist at all times.
Position Eucalyptus gunnii in full sun out of any direct wind. The rich colours of the juvenile leaves are most effective when the plant is used as a foil for the Summer colours of pale blues, pinks and white, and the pot should be placed behind other displays for maximum effect.
Keep the plant’smoist at all times during the Summer; for the remainder of the year, water thoroughly, then allow the surface of the compost to dry a little before giving the next thorough watering. Stand any container on feet or pieces of tile to ensure free drainage and prevent waterlogging.
This plant of the southern hemisphere has no need of any additional humidity: the foliage is quite fleshy and can tolerate dry air very well.
Top-dress established plants in Spring with a general-purpose fertilizer. Only feed plants that have moist compost.
Grow this plant in a free-draining, loam-based compost: use a compost with added horticultural sand or grit, or even add your own – up to a quarter by volume. This will ensure that the plant is stable; in addition, use a large container. Repotting is an unlikely option: once potted plants begin to falter, plant them out in the garden and replace them with new stock.
Look for tender Eucalyptus species, which are more suitable for the cold conservatory. The Lemon-Scented Gum (Eucalyptus citriodora), the Tasmanian Blue Gum (Eucalyptus globulus) and Silver Top (Eucalyptus nitens) are all good container plants, which need frost protection, unlike the Cider Gum.
Discoloured foliage usually indicates that the plant is suffering from. Excessive cold: position it out of cold winds.
Dead foliage may occur after a late frost – delay pruning as long as possible – as late as May in the UK.
Leaf distortion and insects present in Summer may indicate a pest called the Blue Gum Sucker: use an insecticide dust, as the waxy leaves repel water-based products. Most damage occurs from the sooty moulds that grow on the suckers’ honeydew.