A spreading or erect shrub which grows to 2 metres high and 1 metre wide, usually with hairless stems.
It has a mainly coastal occurrence in NSW, growing close to the coast and inland, in disjunct patches, as far west as Wollemi National Park towards the Hunter Valley (north-west of Sydney / west of Newcastle). It extends along the coast to just south of Fraser Island in Queensland, as well as along most of the Victorian coast and inland central areas, to the east of South Australia, as well as over most of Tasmania.
It is found in dry sclerophyll woodland and open forest, heathy forest and heathland, usually on sandy soils or rocky areas.
Dillwynia is a member of the “pea” family. This generally means that leaves are alternate with stipules at the base of the petioles. Dillwynia have simple and alternate leaves, with stipules present and minute, or absent.
Leaves can be flat, terete or triangular in cross-section and often twisted.
In this species, leaves are linear, to 20 mm long, to 1 mm wide, smooth and generally hairless, with a recurved acuminate tip.
Flowers are, of course, pea-shaped (a term sometimes used is papilionate), with 5 petals in a fixed arrangement; the main back petal is called the “standard”, two lateral petals called “wings” and two fused petals at the bottom called the “keel” (in which the anthers and one carpel tend to be hidden).
In Dillwynia, flowers are yellow, or red and yellow (or orange/yellow) and are usually arranged singly or in small groups in leaf axils or on the ends of branchlets. The upper two of five sepal lobes are joined in a single “lip”. The standard petal is typically wider than high (a useful identification feature), and the keel is the same length as the wings. There are very small leafy bracts present on the common peduncle (which can fall early or be persistent) and bracteoles on flower pedicels (below the calyx).
In this species, flowers are bright yellow, about 10 mm in diameter, and have an orange throat with red markings on the standard. These appear in dense clusters at the end of the wiry branchlets from August to December.
The fruit of all peas is a pod. In this species, they are to 6 mm long, with sparse hairs.
There is not a lot of available information regarding the cultivation of this species. It is known to be cultivated to some extent. It may be temperamental in some locations and garden-habitats. It is found naturally on sandy and rocky soils, so likely needs good drainage to thrive.
Dillwynias are not overly common in cultivation. However, they make very attractive garden subjects with masses of flowers. They are generally suited to well drained soils in a sunny or semi-shaded position and most will tolerate heavy pruning.
Scale insects may be found on the leaves and branches and may be treated with an application of white oil.
Propagation from seed is relatively easy following pre-treatment to break the physical dormancy provided by the impervious seed coat. Pre-treatment can be carried out by abrasion or soak in near-boiling water for about 30 seconds, before cooling rapidly under flowing cold water. Alternatively soak in cold water for several hours. Dry to prevent rotting before sowing. Germination occurs in 3-4 weeks.
Cuttings strike reasonably well using firm, current season’s growth.
Dillwynia is a genus of about 40 species of flowering plants endemic to Australia and occurring in all Australian states and the Australian Capital Territory (except the Northern Territory). They are generally small to medium-sized shrubs. They are often known by the name of ‘Eggs and Bacon’ or ‘Parrot-peas’ because of their bright yellow and reddish tints of the flowers. NSW currently has about 22 taxa.
Dillwynias are often colonising species germinating quickly after fires to stabilise the soil and provide nitrogen. All are legumes able to “fix” nitrogen from the atmosphere in nodules on their roots.
The following link is a list of Dillwynia species accepted by the Australian Plant Census and Plants of the World Online as at May 2021: https://en.wikipedia.org/wiki/Dillwynia
Dillwynia spp. will mostly regenerate from seed after fire.
Dillwynia – honours Lewis Weston Dillwyn (1778-1855) was a British porcelain manufacturer, naturalist and Whig Member of Parliament (MP). He was also renowned for his published works on botany and conchology.
glaberrima – from Latin glaber meaning “without hair”, referring to the leaves.
This species is not considered to be at risk of extinction in the wild.
Australian Native Plants Society Australia – Dillwynia glaberrima profile page
NSW Flora Online (PlantNET) – Dillwynia glaberrima profile page
Wikipedia – Dillwynia glaberrima profile page
Cronin, L. (1990). Key Guide to Australian Wildflowers. Reed Books Pty Ltd.