A native of Victoria and South Australia, Grevillea dimorpha is one of the best of the smaller grevilleas, providing a long season of bright red flowers any time between autumn and early spring. It is a very hardy shrub of tough, stiff growth and generally reaches a size of about 1.5 m high and 1 m wide. In light soil and away from strong winds it has been known to reach 1.5 m high and 2 m wide at 5 years old. The habit of branching is generally sparse with a few main branches, often throwing out one or two angular branches along the ground. However, some plants develop a more curving and bushy form from ground level.
The stiff leaves are mostly alternate and, like the branches, uneven in spacing and length, varying from 5-15 cm long on the same plant; likewise the leaf stage is extremely variable. There is one form of the species with very narrow leaves pointing upwards close to the stem, and another form has leaves up to 2 cm wide, either straight or curving outwards. Their colour is mid green, rather dull on the upper surface and silvery beneath.
During spring and summer this shrub may go unnoticed as its general appearance is not outstanding, specially when grown in a harsh dry situation, but as soon as the flowers open it becomes a shrub of distinction. Blood-red spider flowers with long, stiff styles up to 5 cm long, set in the axils of the leaves, are very showy against the open outline of the plant. If several specimens are grown in the garden they may not all flower at the same time, but over a period from the end of May till the end of November, quite unaffected by the coldest winter weather. The last one appears in early December, fading with the heat, and eclipsed by brighter species flowering at this time.
The species may be propagated from tip cuttings taken in midsummer. Nurseries specialising in native plants stock this shrub, and it should be planted in lime-free light soil, where it will come into flower at an early age.
Though this shrub is drought hardy, soft, bushier growth may be encouraged
by good watering and tip pruning when young. Occasionally scale and the associated
black smut may give trouble, but control may be exercised by spraying with a
systemic insecticide solution in white oil.
Based on text by ANBG staff (1972)
Name meaning: Grevillea dimorpha
Grevillea - after C. F Greville, one-time patron of botany and President of the Royal Society, London;
dimorpha - having two forms, one with broad and the other with narrow leaves