Beware of the blue passion flower!
Blue Passion Flower ( Passifloracaerulea) (Category 1b throughout South Africa)
What does it look like?
A vigorous climber with palmate leaves and bright orange, oval fruits which hang from long stalks. The leaves are dark olive-green. The flowers are large, spectacular, typical Granadilla-like flowers. The plant is semi-deciduous. It is a common boundary fence vine in Grahamstown, and also typically grows amongst other vegetation in gardens.
Where does it come from?
South America.
Why is it bad?
This is an aggressive vine that smothers indigenous vegetation by forming a dense net on top of trees.
It is spread by birds, and can be found just about anywhere in our area, including gardens, waste areas, riverlines, orchards, farmlands and even in open veld. It is extremely hardy, and is one of the first plants to colonise disturbed areas, including areas recently cleared of other invaders. In South Africa, it is mostly troublesome in the Eastern Cape and KwaZuluNatal. It is also considered to be invasive in parts of East Africa, North America, Spain, Australia, New Zealand and various Pacific Ocean islands including Hawaii.
How can I control it?
Fortunately, it is usually possible to find one main stem with larger vines (unlike the multiple-rooting points in other local invasive creepers, such as Pereskia and Catsclaw Creeper).
The simplest method is to cut the main stem about 20cm above the ground, scrape the outer skin off the stem (down to the ground), and paint the exposed part with a 2–5% concentration of Roundup (in water).
Alternatively, you can scrape the skin off 20 cm sections of the main stem along its length and paint as above. Even smaller vines can have a tough rootstock, and cutting and treating with herbicide is a better guarantee of killing the plant than hand-pulling (as they often break off in the soil). Seedlings can be hand- pulled. Regular follow-ups will be necessary as birds will continually re-introduce the seeds. We have found that simply treating the cut end and foliar spray are both ineffective.
What can I replace it with?
Although Grahamstown seems to be a hot-spot for invasive boundary fence creepers (although not as bad as Pietermaritzburg!), there are numerous indigenous replacement options. These include various succulent Canary Creepers (e.g. Senecio macroglossus, S. macroglossoides, S. tamoides), Port St Johns/ Zimbabwe Creeper ( Podranea ricasoliana/brycei), Plumbago ( Plumbago auriculata), Black-eyed Susan ( Thunbergia alata), Flame Lily ( Gloriosa surperba), Cape Hon- eysuckle ( Tecoma capensis), Wild Grapes (e.g. Rhoicissus tomentosa), Starry Wild Jasmine ( Jasminum multipartitum), Wild Clematis ( Clematis brachiata), some indigenous morning glories (e.g. Ipomoea cairica and the vivid I. ficifolia) and climbing varieties of Pelargonium. • For alien invasive species advice, property assessments, alien control plans and practical implementation of control actions, contact The Alien SWAT Team: Dr Ralph Clark 072 439 8981, Mr Timothy Mattison 060 527 7816; thealienswatteam@gmail.com.