Most of the subjects illustrated are parents used in Prima Bio's breeding programme.
Eucalyptus caesia subspecies magna, also known as 'Silver Princess' is a large shrub or small tree that is widely-grown in Australia. It is most suited to Mediterranean climates, but appears to tolerate mild wet winters quite well and has slight frost tolerance. It can flower freely when grown under cover in the UK. Prima Bio has produced a E.gunnii x caesia spp magna hybrid.
Eucalyptus pulverulenta is a straggly hardy shrub or tree from New South Wales. It is normally cultivated for its striking foliage, which is used in floristry. This specimen is in Lamberhurst, Kent. It is the variety 'Baby Blue'
The flowers of Eucalyptus pulverulenta 'Baby Blue'. This dwarf variety was selected in California in the 1950s. It grows true from seed and is widely-grown for cut foliage. Like the wild-type, it flowers very freely from a young age. The flowers produce great quantities of nectar and are a magnet for insects. However, in the UK it flowers in winter whereas the wild-type flowers in summer.
Eucalyptus vernicosa is a very variable species in nature. It is hardy, and sold by several nurseries in the UK; such plants tend to be of the more vigorous forms and produce small trees. The photo shows an extremely dwarf, prostrate form growing near the summit of the Ironbound Range in SW Tasmania. In cultivation, such provenances are very slow-growing and retain their prostrate habit.
Book-leaf mallee (Eucalyptus kruseana) is an attractive shrub native to the western goldfields. It is cultivated in Mediterranean climates around the world. A specimen growing in a polytunnel at East Malling, Kent flowered in spring 2006 and 2007.
Eucalyptus lehmannii (Bushy Yate) is a mallee shrub. It is one of a number of Western Australian species that have clusters of horned flower buds. The 'horns' are opercula that contain the very long yellow stamens before the flowers open. The unusual flowers are probably adapted for pollination by birds or small mammals.
Eucalyptus cordata ssp quadrangulosa is a well-shaped medium-sized tree. It is one of a number of species that usually retains its distinctive 'juvenile' type of foliage when mature. It is moderately frost-tolerant but is mainly found in milder parts of the UK. This specimen, 25 years old, is at Plas Newydd, Anglesey.
Tallerack (Eucalyptus pleurocarpa) is a straggly but attractive shrub native to the south coast of Western Australia. It is cultivated for cut foliage in Australia and California. It has no frost-tolerance, but is otherwise very easy to grow in containers and is seemingly free of pests and diseases when grown under glass. There is a mature specimen in the temperate greenhouse at the Royal Botanic Gardens, Kew. It belongs to a distinct group of eucalypts (the Eudesmia sub-genus) and it is most unlikely that it could be hybridised with any hardy species. The photo shows a young coppice shoot growing from the base of a mature specimen in the wild.