The Hibbertia genus belongs to the Dilleniaceae family and consists of some 120 species of small evergreen shrubs and climbers. Most of these species are native to Australia. They are often called by the common name of ‘Guinea Flower’.
Members of this genus generally have bright yellow (sometimes orange) flowers with 5 separate, flat petals. The flowers are borne singly. Flowering is mostly during spring and early summer with some species flowering randomly throughout the year.
Ideal for a rock garden is Hibbertia miniata, a small erect shrub which, in the wild, is confined to the jarrah forests of Western Australia. The leaves are broad and grey-green and the flowers are very showy with dark purple anthers.
Hibbertia empetrifolia (also known as H.astrotricha) is commonly known as the trailing guinea flower. It is native to south eastern Australia and has very small, oblong leaves which are dark green, in colour. It is a low shrub with trailing, wiry stems. The flowers are a bright yellow with a diameter of 12mm.
The cutleaf guinea flower (Hibbertia cuneiformis) grows to 3 metres with a spread of about 1.5 metres. The leaves are oblong and toothed. It is an erect bushy shrub with a tendency to twine. The deep golden flowers appear at the end of the branches in spring and summer. They may appear at odd times throughout the year as well. It comes from the coastal districts of the southern regions of Western Australia so is suited to seaside gardens.
A species that will grow in full sun or partial shade is Hibbertia aspera (rough guinea flower). This spreading shrub occurs in eastern and south-eastern Australia. It has small, dark green leaves and bright yellow flowers of 12mm diameter. This species also flowers throughout the year.
Hibbertia pedunculata or Slender Mint is a low growing, highly aromatic groundcover. This native mint spreads by layering and grows well over a wide range of conditions. It has spikes of small mauve flowers from September to February.
Hibbertia scandens, also known as the Climbing Guinea-flower, is a vigorous climber with long, trailing stems and shiny green leaves. Bright yellow, open-petalled flowers about 7cm in diameter are produced through most of the year with the peak flowering season being from November to January. Initially, it can be slow-growing. It sometimes suffers from frost damage but will cope with exposed coastal conditions.
It is the small shrubs and climbers of this genus that are most familiar to gardeners. Hibbertia are ideal in containers, rock-gardens and as groundcovers. It is easy to grow and likes moderately fertile soil which needs to drain well but not dry out too quickly. In hotter areas, it will prefer partial shade. Most are affected by frost and will need some protection especially while the plants are young. Pruning the tips while young and after flowering will help maintain a good shape.