Eucalyptus johnstonii
| Eucalyptus johnstonii | |
| Light: |  |
| Moisture: |    |
| Hardiness: | 8 |
| Soil pH: | 5.6-8.4 |
| Evergreen | |
| Height: | 197' |
| Speed: | Fast |
| Open Woods Forest | |
| Native to: | |
| Shelter | |
| Tea: | Yes |
 | |
Eucalyptus johnstonii (common name: yellow gum)
Propagation: Seed - surface sow February/March in a sunny position in a greenhouse[1][2][3]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c[4]. Pot up the seedlings into individual pots as soon as the second set of seed leaves has developed, if left longer than this they might not move well. Plant out into their permanent positions in early summer and give them some protection from the cold in their first winter. The seed can also be sown in June, the young trees being planted in their final positions in late spring of the following year. The seed has a long viability[4].
Cultivation: Prefers a sunny position in a moderately fertile well-drained moisture retentive circum-neutral soil[4]. Dislikes clay or chalk soils but succeeds in most other soils[5]. Tolerates poor soils, especially those low in mineral elements[4]. Tolerates dry soils and also drought once it is established[4]. Tolerates maritime exposure, though the foliage may be burnt.
A fairly hardy species, it tolerates long periods down to -6°c and short periods down to -9°c[6]. Plants are hardy to between -15°c and -20°c according to another report[4].
Eucalyptus species have not adopted a deciduous habit and continue to grow until it is too cold for them to do so. This makes them more susceptible to damage from sudden cold snaps. If temperature fluctuations are more gradual, as in a woodland for example, the plants have the opportunity to stop growing and become dormant, thus making them more cold resistant. A deep mulch around the roots to prevent the soil from freezing also helps the trees to survive cold conditions. The members of this genus are remarkably adaptable however, there can be a dramatic increase in the hardiness of subsequent generations from the seed of survivors growing in temperate zones[4].
Eucalyptus monocultures are an environmental disaster, they are voracious, allelopathic and encourage the worst possible attitudes to land use and conservation[4].
This species is sometimes included as a sub-species of E. vernicosa[1].
Plants are shallow-rooting and, especially in windy areas, should be planted out into their permanent positions when small to ensure that they do not suffer from wind-rock[7]. They strongly resent root disturbance and should be container grown before planting out into their permanent position[1].
The flowers are rich in nectar and are a good bee crop[4].
Range: Australia - Tasmania.
Habitat: Usually found on badly drained sandstones from 600 - 2600 metres[8].
Usage: Tolerates maritime exposure, though the foliage may be burnt, and it can be grown as a shelter belt tree[9].
Wood is of high quality[8].
Pollinators: Bees
Soil: Can grow in light, medium, and heavy soils.
Drainage: Prefers well drained soil.
Wind: Tolerates maritime wind exposure
In Leaf: Evergreen
Flower Type: Hermaphrodite
Known Hazards: Citronellal, an essential oil found in most Eucalyptus species is reported to be mutagenic when used in isolation[10].
In large doses, oil of eucalyptus, like so many essential oils has caused fatalities from intestinal irritation[10]. Death is reporte
Also Known As: E. muelleri. T.B.Moore. E. subcrenulata
Links
References
- ↑ 1.0 1.1 1.2 Bean, William. Trees and Shrubs Hardy in Great Britain. Murray, 1981.
- ↑ Sheat, Wilfrid. Propagation of Trees, Shrubs and Conifers. St Martin, 1948.
- ↑ Rice, Graham. Growing from Seed Volume 2. Thompson and Morgan, 1988.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
- ↑ Gordon, A and D Rowe. Seed Manual for Ornamental Trees and Shrubs. 1982.
- ↑ Brooker, M. A Key to Eucalypts in Britain and Ireland. HMSO, 1983.
- ↑ Genders, Roy. Scented Flora of the World. Robert Hale, 1994.
- ↑ 8.0 8.1 Kelly, Stan. Eucalypts. Nelson, 1969.
- ↑ Rosewarne Experimental Horticultural Station. Shelter Trees and Hedges. Ministry of Agriculture, Fisheries and Food, 1984.
- ↑ 10.0 10.1 Duke, James. Handbook of Energy Crops. 1983.