A spreading to erect shrub, growing to a height of 1 metre, spreading to 1 metre wide, with tiny hairs on the stems.
It grows primarily in the Greater Sydney area, from Berowra in the north, to Bowral in the south (mainly through western Sydney on the Cumberland Plain); then with a disjunction from around Jervis Bay to west of Tuross Head, along the NSW South Coast.
It is found in dry sclerophyll woodland and forest, on shale and alluvial soils. Often, it is found in open disturbed areas such as cleared clay-pans which are absent of trees.
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 clustered along the stems, twisted, narrow oblong, to 4 mm long by less than 1 mm wide, with small tubercules (glands) and 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, the flowers are arranged in umbels of up to six on a peduncle up to 3 mm long, yellow in colour. The standard petals are to 7 mm long with red markings; flowering mainly in late winter-spring.
The fruit of all peas is a pod. In this species, they are approximately 5 mm long.
There is not a lot of available information regarding the cultivation of this species. It may be more widely cultivated in the future. It can likely be cultivated on clayey to alluvial soils. May be short-lived. Low shrubs can form a light spreading ground cover. Prune after flowering to maintain shrubby growth.
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) 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.
parvifolia – Latin – parvus meaning “small” and folia meaning “leaves” – capturing the very small leaves of this species.
This species is not considered to be at risk of extinction in the wild. It is considered rare in Sydney and is not often seen in large numbers.
NSW Flora Online (PlantNET) – Dillwynia parvifolia profile page
Wikipedia – Dillwynia parvfolia profile page
Fairley, A. (2004). Seldom Seen – Rare Plants of Greater Sydney. New Holland Publishers (Australia) Pty Ltd.
Denise Greig (1996). Flowering Natives for Home Gardens. Angus & Robertson