All indigenous plants are protected by law and it is illegal to collect seed or propagate material of any native plant without a permit from the Victorian Department of Sustainability and the Environment. However, by working with the Friends of Westgate Park or St Kilda Indigenous Nursery Cooperative (SKINC) you can learn a great deal about local plant propagation while adhering to the regulations that are in place to ensure the continued survival of our local ecosystems. The seed which a plant produces is not only important to its own reproduction, but also to the survival of many species of seed-eating fauna.
There are over 300 plant species in the Park, around 15 of which are thought to be remnant (ie. remaining from the time of colonisation) and there is a variety of means by which they reproduce. Plants are pollinated by wind and insects and birds which transfer pollen to fertilise the flower of that plant. Like all life forms, plant genetic diversity is integral to ensuring vibrant and healthy plants, so collecting from an area with a strong population is vital. The Friends of Westgate Park have made it part of their mission to ensure that rarer plants within the region are both numerous and healthy so seed production is plentiful.
Many plants have ingenious methods to attract and encourage fertilisation. Most species of orchids, for example, replicate the reproductive systems of native wasps and bees so that these species confuse the flower with a potential mate. On attempting to mate with a number of flowers, these insects pollinate the flowers. Many species have sweet nectar which birds and insects are attracted to which also encourage fertilisation.
Trigger plant, Stylidium graminifolium, has a flower with a protruding ‘arm’ filled with pollen. This arm is ‘triggered’ into ‘slapping’ the insect’s back while an insect drinks nectar fro the flower. As the insects drink from each flower within a diverse population of these plants, pollen is transferred from flower to flower, fertilising each flower. Once the seed is pollinated, each plant has it’s own mechanism for when it may decide that conditions are right to germinate. For many species pollinated by wind, a combination of sunlight and rain is necessary for successful germination. Most of the local daisy species germinate by this method. Some species will only germinate after a cold winter, therefore seeds require refrigerating to germinate.
Many species produce fruit which birds eat and seeds are germinated after being digested in their gut. The spread of these species in nature occurs randomly in bird scats, and can be difficult to replicate in a nursery environment. However, research into reproducing the acids of bird guts has enabled some of these species to be successfully propagated.
As a fire prone country, many local species respond to fire. Some simply respond to the heat of fire, but others respond the chemicals in the smoke. Just over a decade ago, a Western Australian botanist discovered that by reproducing the chemicals created by bushfire smoke in a nursery environment significantly increased the germination rates of some species of seeds.
For some species, the ‘code’ has not been cracked into how the species germinates in nature. These species either rapidly become extinct, or are currently only grown by cloning – cuttings. While the Park has a few species which are only grown by cuttings, both FOWP and SKINC are continually attempting to grow these plants from seed to enable genetically diverse populations within the Park and over the last decade many species in this category are now successfully grown by seed thanks to the diligent work and collaboration between both FOWP and SKINC.
Volunteers go to work collecting seed and separating it from the pod.
At both Westgate Park and at SKINC, spring and summer is the time to boil, freeze, or smoke our seeds to enable new plants to grow and thrive. While this task takes the least time of the nursery duties – it is the one that requires the most expertise into understanding how each individual species reproduces itself.
We like to show our volunteers how, after being sprayed with smoke water, grass seeds ‘wriggle’ themselves into the ground to get to a stable environment in which to germinate. This is a truly fantastic sight to see!