Pea species

There are over 12,000 pea species across the globe including herbs, shrubs, climbers and trees. In the Canberra region there are about 125 species, mainly native shrubs (such as Daviesia, Dillwynia and Pultenaea) and introduced herbaceous pasture species (such as clovers and lucerne). They are good colonisers of bare areas assisted by their ability to trap nitrogen from the air and increase soil fertility. Many of the native species are dispersed by ants and will flourish after fire.

The native herbs and smaller shrubs are vulnerable to live-stock grazing and mainly occur in areas where grazing has been excluded or intermittent, such as within some Travelling Stock Reserves. Peas now rare in our region as a result of agriculture include all four of the locally occurring Swainsona species, Tough Scurf Pea, Large Tick-trefoil, Grey Parrot-pea, Tick Indigo, Austral Trefoil, Pultenaea laxiflora and Zornia.

About 25% of the peas in the wider Canberra region are introduced weeds.

Although relatively few in number woody introduced peas, such as brooms, Gorse or Tree Lucerne are significant weeds. Exotic woody peas are a poor planting choice, as they are likely to stray far beyond the garden path.

All flowers of this family have the “sweet pea” butterfly shape, comprised of five often brightly coloured petals: the large upright standard at the back, two small lateral wings and the lower keel of two petals that are mostly fused.

Pea plants are generally distinguished from each other by their form (herb, shrub etc), their leaf characteristics, the colour of their flowers and the size and shape of their seed pods. Ideally postings of pea plants will include photographs that encapsulate all these features.

Photographs should show whether leaves are a single blade, or if not the number of leaflets of which they are composed. Photographs should also try and capture the pair of stipules or appendages that may occur at the base of the leaf stem. They can be leaf-like, membranous or spine like. 

Some interesting pea plants in our area include the Murrumbidgee Bossiaea, a wiry shrub, which is restricted to the ACT and the Michelago Parrot Pea, which has bluish-green leaves and is only found within the Southern Tablelands of NSW. Vanilla Glycine and Twining Glycine are two locally occurring perennial peas that are seen as an important genetic resource for breeding rust resistance and other desirable traits in to their near relative Glycine max (Soya Bean).