2-7 deg C/36^5 deg F
There are a number of eucalypts that make very attractive foliage plants in their young state. Unfortunately, all of them will eventually become too large. and they usually form adult foliage which is quite different from the more decorative juvenile types. Many species can be grown from imported, so it is usually not much trouble to raise fresh, young plants to replace old ones which have outlived their usefulness.
Two species are of particular interest as houseplants. E. globulus, the blue gum. is almost hardy and useful for chilly places. provided there is plenty of light. If allowed to grow to an appreciable size it can be put in hallways, foyers and porches, where it will make an impressive sight. Theon young plants are greyish-blue-green. When crushed they emit the familiar pungent smell of eucalyptus oil used in the treatment of nasal colds. Quite different is the species E. citriodora,
native to Queensland. This is popularly called the lemon-scented eucalyptus, because in this case the leaves have a pronounced sharp lemon scent. In warm conditions, the plant will scent the air of the room and is very pleasant. The leaves are pointed and elongated, pale green and covered with short, bristly hairs. It is a very desirable houseplant and can be kept bushy and compact bythe growing tips of young shoots. If this is not done, the plant will become tall and spreading and there may not be space to keep it for more than two years or so. This species is also less cold resistant and needs a minimum of about 7 deg C (45°I’) in winter. It also prefers a more humid atmosphere, and will wilt rapidly if the is allowed to become too dry.
Both species are quick growers and the pot size should be restricted to discourage rampant development. It is most unusual for eucalypts grown as houseplants to be troubled by pests or diseases. The lower leaves of E. citriodora may sometimes turn reddish in colour ifis erratic.