Rain Forest Vine: Slender Grape (Cayratia clematidea)
I came across a good specimen of a local Australian native plant called Cayratia clematidea, commonly known as Slender Grape, in the bush one day and decided to make a video and write this article about it. It's a member of the Vitaceae family which also contains edible grapes as well as Cissus vines, another commonly occurring native vine in bushlands around Brisbane, Australia and many other regions areas as well.
Cayratia clematidea grows as a a herbaceous scrambling climber with stems to 2m long that occurs on the edges of rainforests north of Shoalhaven Gorges in New South Wales, Australia. It’s a pioneer species, filling sunny gaps and this combined with its soft foliage can give it a weedy appearance. Although it can be easily pruned away it has the potential to smother small plants but isn't vigorous enough to kill established trees.
Slender grape flowers during Summer with clusters of small greenish-white flowers with 4 petals borne on long, multiple-branched stalks. The 5 to 7 mm wide berries that follow start off green and turn black as they ripen. Each fruit contains 2 to 4 seeds and the fruit are eaten by birds which disperse the seeds.
The leaves of Cayrtia clematidea are compound and alternate and are comprised of 5 leaflets in a palmate (or palm shaped) arrangement. The 2 leaflets closest to the stem on either sides arise from the same vein branch. The furthest leaflet is normally the largest with the 2 closest to the stem being the smallest. The leaflets are lobed and are not glossy on either above or below surfaces. The stems, leaves and flowers can also sometimes have sparse hairs. The leaves are the food plant for the larvae of the Joseph's Coat Moth, Agarista agricola. The leaves normally will always have either have a tendril or a flower inflorescence opposite them.
The tendrils of Cayratia clematidea help it to climb by wrapping around other plant stems or by adhering to a rough surface such as the bark of trees. The tendrils typically are 3 tiped with the end 2 forming a fork, however if the tendril doesn't find anything to attach to it can branch several more times.
Mistaken Identify: Slender Grape or Balloon Vine?
People new to bush regeneration often confuse slender grape with the exotic pest balloon vine (Cardiospermum grandiflorum) which has 9 leaflets instead of 5 but otherwise looks quite similar. I've accidentally pulled a few out myself too, as they can sometimes be tangled in amongst other weeds and vines. Fortunately the plant forms an underground tuber up to 5cm in diametre from which it can reshoot. In fact, the local indigenous people gathered the tubers of this species and prepared them by beating them on stones before roasting them. It often dies off in dry periods during Autumn and sprouts again in Spring from these underground energy reserves. These tubers also give the plant the ability to re-sprout after fires.
Where to find Cayratia clematidea to grow at home?
As this is an Australian native plant which is not widely known in the horticultural industry, you will have little luck finding it in conventional plant nurseries and garden centres. Instead seek out specialist local native plant nurseries in locations where it can be found growing naturally in the wild. Ebay sellers may also have the seeds from time to time. Unfortunately, people outside Australia will find it almost impossible to source the seed as most Australian sellers do not export due to quarantine regulations.