An erect shrub growing to 2.5 metres high with hairy stems.
It has a scattered and large natural distribution, with high concentrations of records in the Greater Sydney area in NSW, extending north-west past Kandos and up to Merriwa, as well as north of Bathurst, through Sydney and the Gosford-Wisemans Ferry-Bucketty area, south through Wollongong to Jervis Bay and Ulladulla (and west of). It is found again with a disjunction, north of Nelson Bay and extends up the coast and hinterland to north of Bundaberg in Queensland.
(There are online records which show that it grows in the western half of Victoria (again with a disjunction); however, these populations have been reclassified as D. sericea).
It generally grows in dry and wet habitats on sandstone, in heath and woodland.
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 crowded along the branches, linear, oval in cross-section, with a longitudinal groove on the upper surface, to 20 mm long by only 1 mm wide, with a half-twist and mostly glabrous.
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 arranged in pairs in leaf axils near the ends of branches but often extending down the branches. The flowers are sessile or on a very short peduncle with bracts 1–2 mm long and shorter bracteoles near the keel. They are yellow with red to brown markings on the standard and keel, with the standard to 12 mm long; and are closely packed; occurring in July to October.
The fruit of all peas is a pod. In this species, they are to 7 mm long, oval to rounded.
There is not a lot of available information regarding the cultivation of this species. It is known to be cultivated to some extent. It is highly recommended to plant it on a well-draining sandy soil.
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.
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) who was a British porcelain manufacturer, naturalist and Whig Member of Parliament (MP). He was also renowned for his published works on botany and conchology.
floribunda – Latin – meaning “abundance of flowers”.
This species is not considered to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Dillwynia floribunda profile page
Wikipedia – Dillwynia floribunda profile page
Australian Plants Society – Sutherland Group – Coastal Plants of the Royal National Park CD – Dillwynia floribunda profile
Denise Greig (1996). Flowering Natives for Home Gardens. Angus & Robertson.
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.