Coloured spider orchid

Coloured spider orchid

The coloured spider orchid (Caladenia colorata) is a nationally endangered plant found in just a handful of properties in the Murraylands and Riverland region. Conservation efforts are focused to try and protect the remaining specimens and support their natural propagation.

What is the coloured spider orchid?

The coloured spider orchid is a native orchid which was historically found in low rainfall zones across South Australia and Victoria. It has dull-green leaves with a reddish base that vary in length from 4-10cm. Plant stems range from 5-30 cm long and are red and hairy. Each plant produces 1-2 striking flowers which are cream-green and marked with red and or purple-brown markings.

Coloured spider orchid

Coloured spider orchids flower between August and September and sometimes produce a faint petrochemical smell.

Where are coloured spider orchids found?

The coloured spider orchid grows in sandy, fertile soils but also in rocky outcrops. The species is found in woodland, open woodland and mallee woodland habitats where the ground is scattered by shrubs and grasses. In addition to their habitat and climate requirements, this rare species relies on a specific mycorrhizal fungi to grow, making it difficult to propagate them artificially.

In the Murraylands and Riverland region, coloured spider orchids are found around Callington, Tailem Bend and the Coorong, with just a handful of populations known to still exist. The neighbouring Hills and Fleurieu region includes the most significant concentration of coloured spider orchids with around 4,000 known plants around Hartley.

Why are coloured spider orchids under threat?

Coloured spider orchids were once found in a continuous stretch of land from the Adelaide Hills, through the Limestone Coast and into western Victoria, but the loss of woodland to make way for agriculture significantly impacted the spread and populations of the species.

Coloured spider orchid

Currently, the most significant threat to the species is grazing by livestock, pests and native animals. The coloured spider orchid is also vulnerable to being smothered by weeds (bridal creeper, perennial veldt grass, wild turnip, African boxthorn, capeweed, false caper and pussytail grass), as well as the effects of recreational activities, rubbish dumping, road maintenance, vegetation clearance, trampling and illegal collection.

Coloured spider orchids require very specific conditions to grow and reproduce which makes them incredibly difficult to propagate artificially. As well as favouring woodland habitats and certain climatic conditions, the species relies upon its relationship with a mycorrhizal fungi. To reproduce, the coloured spider orchid needs a male black thynnid wasp for pollination. Protecting existing populations of the species is therefore essential for their survival.

Coloured spider orchid
Image by Reiner Richter under a CC BY-NC 4.0 Deed

What is being done to protect coloured sider orchids?

Coloured spider orchids are found on just 2 or 3 private properties in the Murraylands and Riverland region, in addition to the Coorong National Park. Landholders have been supported by our ecologists to protect populations through fencing and the control of pest plants and weeds. Many landholders have opted to protect coloured spider orchid habitat through native vegetation heritage agreements which are established in perpetuity and there are grant programs to help landholders with fencing and pest control costs.

Ecologists from the Murraylands and Riverland Landscape Board help to monitor populations through regular surveys, as well as supporting landholders with known clusters. Future work will focus on the effects of prescribed burning which is expected to produce positive outcomes by opening up woodland habitat.

What should I do if I see a coloured spider orchid?

If you’re lucky enough to spot a coloured spider orchid, the most important thing to remember is to not touch or remove it. Take a photo and be discreet about its location in order to protect it from illegal collection.

If you suspect you have a population of coloured spider orchid on your property, contact our Ecologist who will help to formally identify the plant. They can also offer support and advice to help conserve and enhance this endangered species so you can play a vital role in native biodiversity.

Contact our Ecologist

Unit 5-6, Level 1 Sturt Centre, 2 Sturt Reserve Road, Murray Bridge SA 5253

0459 799 217

victoria.hefford2@sa.gov.au