Derwentia

Text and images by Warren Sheather

Derwentia arcuata	Derwentia arenaria	Derwentia perfiolata

Derwentias are members of the Scrophulariaceae family in company with the exotic Foxgloves and Snapdragons. Some species may be synonymous with the Veronicas.

They are usually semi-woody, small shrubs with leaves that are opposite, entire, toothed or deeply lobed. Inflorescences are in terminal racemes containing many individual flowers. Flowering usually occurs during late spring and summer. A few species bloom in autumn.

Three Derwentias have performed well in local gardens. They have proved to be hardy, free-flowering and propagate easily from cuttings.

Derwentia arcuata is a local species. There is a small population on a rocky outcrop near the Sport’s Union at UNE. Derwentia arcuata is a small shrub reaching a height of one metre. Plants have multiple stems. Leaves are narrowly ovate, sessile and curved downwards. Between September and February each stem is crowned by a 35 centimetre long raceme that is crowded with lilac flowers. Blooms are profuse and conspicuous. Plants should be pruned after flowering. This promotes fresh growth and bounteous blooming.

Derwentia arenaria is found from south-eastern Queensland to the Central Western Slopes of New South Wales. This multi-stemmed shrub grows to a height of 1.5 metres. The leaves are light green, linear with narrow lobes. Each stem carries a long raceme of violet-blue flowers from September to May. Blooms are often visited by native Blue-banded Bees. Once again this species benefits from pruning after the flowers fade. This beautiful small shrub deserves a place in the native garden. Cottage gardens and rockeries would benefit from the inclusion of this Derwentia.

Derwentia perfoliata is known as “Digger’s Speedwell” and is another small, multi-stemmed shrub. The leaves are ovate, tightly clustered around the stems in whorls of three. The foliage has a startling similarity to the juvenile foliage of some Eucalypts. The flowers are carried in typical Derwentia racemes. Blooms are purplish-blue, appear between September and February and are both profuse and conspicuous. Foliage and flower are attractive features.

Derwentias are small enough to be accommodated in most gardens. They could be grown as foreground plants in garden beds, in rockeries and cottage gardens as well as container cultivation.

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