Rare and shy sticky emu-bush likes to be disturbed

Here's the thing. A plant can be rare and under threat of extinction, but also require disturbance to grow. That is, fencing off its habitat and leaving it lone will only exaserbate the problem.

The Varnish Bush, an emubush called Eremophila visicida, from sandy loam country between Latham and Pindar in Western Australia, is one such species.

Despite being found over a relatively wide area in the midwest and wheatbelt of Western Australia cal area and being a 'disturbance opportunist', the Varnish Bush is listed as Critically Endangered in that State.

In addition to lack of distrubance, threats include competition from weeds (often also liking disturbance of course), salinity and waterlogging, erosion, inappropriate fires, chemical drift, and grazing by stock and feral animals. And, interestingly, the wrong kind of disturbance through maintenance activities for roads, powerlines and firebreaks.

In response to the combined risk, there are (or at least were, back in 2003) a couple of thousand seeds held in the Western Australian Threatened Flora Seed Centre, and a selection of plants from some of the extant populations grown by the Botanic Gardens and Parks Authority.

So what is this plant? Well it was first noticed by scientists 100 years ago, then found in various locations over a 290 km strip. Even though we now know of 16 separate populations, there are only just over 800 mature plants in nature.

It has sticky branches, leaves and flowers. Hence the common name. The petals of these flowers are spotty inside, yet my photographs here from Perth's Kings Park in late September are missing those vital parts (only the outer layer, the calyx, is visible). I think it's because the flowers are not fully opened.

There is no known use of the plant by Indigenous people living in midwest or wheatbelt areas.

Only at one site is there good active recruitment, with plentiful young plants. It's unclear from the Draft Recovery Plan what kind of disturbance would help this species, except that maintenance disturbance is not the right kind.

The resinous leaves are assumed to be highly flammable and there is good evidence it resprouts at least when roots are disturbed. So the 'right' fire frequency might help. Seed stores reasonably well but from trials done prior to 2003, raking, burning and smoke did not work as stimulants for germination.

Which all makes it difficult for conservation action. Advice to people who have plants on their property is to avoid anything that might damage plants. I guess it's difficult to advise owners to disturb the plants just a bit, but not too much.

By the way, if you want to grow it at home, look for a specimen grafted onto a Myoporum. Based on a survey reported in the 2016 Eremophila Study Group Newsletter, if you want more flowers tip prune or don't prune at all, and plant in a sunny place. Soil doesn't seem to matter with plants doing as well on clay as on sand.