Flora and forest cover
Jean Geue
The vegetation at Ginninderra Falls is very special with a rich native flora surviving in the protection of its steep gorges. The walking tracks in the Ginninderra Falls area take one through a variety of ecosystems. The differences in altitude result in different mix of plants at each level and each change of slope. More than eighty native species have been identified and this diversity provides resilience for the ecosystems to cope through drought, fire and flooding rains.
Ginninderra Falls has at least three icon species - a delightful crowea that has long been in cultivation, an endangered pomaderris and many stands of callitris pine (commonly known as Cypress pines). The latter are one of the few softwood species native to Australia, growing in the dry, inland areas of New South Wales.
Crowea exalata ‘Ginninderra Falls’ with its pink starflowers in winteris an attractive form of a species that has proved popular in horticulture. It is the only place we find it occurring naturally in the Canberra region. There are six pomaderris species listed, one of which is the endangered Pomaderris pallida. These wattle-like shrubs occur in patches, provide a wonderful floral display, but are very choosy about where they live. Callitris endlicheri stands dominate the slopes of the gorge. These pines can be completely killed by fire and are slow to reach maturity. The pine is common in the river corridors, but there are few large stands elsewhere.
A number of species that occur naturally in the gorges have made their way into mainstream horticulture. Not only is it fascinating to see familiar garden plants in the bush, it is critical to protect adequate genetic diversity in the natural populations. Correa reflexa comes in red forms and green ones. Correas have proved themselves in cultivation with many cultivars including the locally developed ‘Canberra Bell’ for our centenary. Hardenbergia violacea and Brachycome species are also in the bush and our gardens. Grevillea juniperina is another popular garden plant that comes from the lower slopes of these gorges.
Ginninderra Falls vegetation may look similar to Molonglo Gorge, but that’s deceptive. Although callitris dominates, the species mix is different. Plants like Styphelia triflora are common in Molonglo Gorge, but don’t seem to appear in Ginninderra Falls. Crowea exalata ‘Ginninderra Falls’ does not seem to occur in Molonglo Gorge nor does Pomaderris pallida. Callitris stands can be wiped out for decades by extensive fire so we must ensure the landscapes are retained in most of the few places where they occur.
There are only two or three steep gorges like this in the Canberra region. They are all very special places in the environment and their protection is essential for keeping species diversity and genetic diversity for each species.
A full composite list of 80 Ginninderra Falls flora is available on request (Jean Geue, 23 June 2011).