Eucalyptus camaldulensis

• Red River Gum

Seed - surface sow February/March in a sunny position in a greenhouse^[10][11][12]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c^[13]. 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^[13].

Prefers a sunny position in a moderately fertile well-drained moisture retentive circum-neutral soil^[13]. Succeeds in most soils^[14], tolerating poor and dry soils, especially those low in mineral elements^[13]. A drought resistant tree once established^[15][13], it is slightly salt tolerant^[15], and can also withstand periodic inundation^[15]. A very fast growing tree^[15]. Plants tolerate an annual precipitation of 103 to 206cm and an annual temperature range of 18.0 to 26.6°C^[1]. It is reported to grow in areas with only 20cm rainfall, but the lower limit for commercial plantations is 40cm. Some provenances tolerate many different soil conditions such as high calcium, high salt and periodic water-logging^[1].The mean maximum temperature of the warmest month where it grows well is ca 29°C. The dry season lasts 4 - 8 months or more and may be severe^[1].

Fairly frost resistant, plants survive temperatures down to at least -7°c in Australian gardens^[15][16]. This figure is not directly relatable to British gardens, however, because of our cooler summers and colder, wetter winters. It could be worthwhile giving this species a try in the milder areas of the country[K]. Some Provenances can tolerate temperatures down to about -5°C and up to 20 frosts per year^[1]. 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^[13]. 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^[13]. Trees are liable to shed branches, especially in hot weather^[14]. This is said to be the most widely distributed eucalyptus tree in Australia, ranging over 23° lat. in most of arid and semiarid Australia but not the humid eastern and south-western coasts. It is regarded as one of the most widely planted eucalypts in the world with more than 500,000 ha planted^[1]. It is planted in Europe, especially in Italy, as a timber crop, for soil stabilization and as an anti-malarial measure^[5]. Some provenances coppice well for six or more rotations, on good sites, plantations are managed on coppice rotations of 7 - 10 years^[1]. Eucalyptus monocultures are an environmental disaster, they are voracious, allelopathic and encourage the worst possible attitudes to land use and conservation^[13]. 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^[17]. They strongly resent root disturbance and should be container grown before planting out into their permanent position^[10]. Survivalists in Australia and elsewhere might learn how the aborigines obtained water from the superficial roots, usually those ca 3 cm in diameter. The roots were excavated or lifted to the soil surface. Then the root was cut into segments ca 45 cm long, debarked, held vertically, and blown into, the water then draining into the receptacle provided^[1].

The flowers are rich in nectar and are a good bee crop^[13].