Rhododendron lochiae and Rhododendron viriosum

Family: Ericaceae

For many years, Rhododendron lochiae was considered to be Australia’s only native Rhododendron, only found growing within the Bellendron Kerr Range inland from Cairns.

However, recent investigations have indicated that two distinct species exist i.e. Rhododendron lochiae and Rhododendron viriosum.

The species are differentiated by R. lochiae having a distinct curved tubular corolla and R. viriosum the shorter and straight tubular corolla.

R. lochiae is found on three peaks Bell Peak, Mt Bartlefrere and Mt Bellenden Kerr. R. viriosum is found north of the Barron River in several geographic locations as far North as Mt Finnigan and as far west as the Windsor Tablelands.

This has been confirmed by research carried out jointly by the Australian Tropical Herbarium, James Cook University with assistance from the Australian Rhododendron Society and DNA analysis done by Massey University in New Zealand. All the botanical work was carried out by Prof Darren Crayn and his staff at Aust Tropical Herbarium James Cook University apart from the DNA work. 

In the garden

To grow Rhododendron lochiae successfully, you will need a raised bed with moist, acid soil with a high organic content to mimic their natural high mountain north Queensland rainforest conditions.

I planted mine about 25 years ago in my garden (in the northern Sydney suburb of Westleigh) and they are now approximately one metre high and about the same wide — yes they are slow growing.

They receive only dappled morning sun and shade for the rest of the day. My plants are happier with some supplementary watering as they flower better and after good soaking rains I am rewarded with a mass display of flowers from late spring through to autumn. The flowers are about 50mm long by 30mm across and occur in terminal clusters of up to six flowers, although the best my plants can do is four flowers. Perhaps my growing conditions are not ideal.

Propagation

Other information

Thanks to Rob Hatcher for clarification on the two species. Rob is Collections Review Project Officer, Botanic Gardens and State Herbarium, South Australia, who was on several of the collecting trips with staff from Australian Tropical Herbarium, James Cook University as a member of Australian Rhododendron Society (and staff at Botanic Gardens Shoalhaven Heads).

Rhododendron: is from the Greek rhodon, rose and dendron, tree, in reference to the terminal flower clusters.

lochiae: named by Ferdinand Mueller after Lady Loch who was the wife of Sir Henry Brougham Loch, who was Governor of Victoria 1884-89.

By Jeff Howes