By Bob and Ena Mcintyre Garden Route

Weeds in our Area(Part One Hundred and Fourteen)

By Bob and Ena McIntyre– Garden Route

BIOLOGICAL CONTROL CONTINUED

Pereskia aculeata (Barbados gooseberry)

Our follow-up subject in the Cactaceae family and Category Oneinvader plantis Pereskia aculeata(Barbados gooseberry).Resembling a climber or scrambler rather than a succulent P. aculeata appears to have been introduced into South Africa from tropical South America as an ornamental and barrier plant. Early records indicate that the plant was recorded in Natal around 1881. It is steadilymoving down the coast and has been noticed along the road between Wilderness and Rondevlei. The Barbados gooseberry was still being promoted in gardening books as late as 1982 as a desirable garden subject. The white to yellowish flowers (see photo) appear between March and July and are followed by edible berries that are spread by birds and animals. In KZN the Zulu people plant the species on graves to prevent vandalism.

Impacts:The species has invaded wild areas in KZN and other sub-tropical regions and as a result large areas have been transformed. The Barbados gooseberry can form a thick and impenetrable hedge, it smothers indigenous vegetation and the unpleasant spines severely restrict access.

Identification:The plant is a spinyvine with long whip-like branches of between 2 and 10 meters (very much like bougainvillaea) and variable from shrubby to clambering. There is a marked difference between young and mature plants.Young stems and leaves are semi-succulent with pairs of short hooked spines (see line drawing of the plant) in the leaf axis. Older stems turn woody with clusters of hard straight spines up to 30-40mm long (see line drawing of spines). Leaves are a bright glossy green. (Flowers and fruit see above).

Control:Unfortunately the single bio-control agent, the leaf chewer Phenrica guerini has had minimal impact on the plant and the only effective control measures are either physical removal or by using a registered herbicide. Two foliar application herbicides are registered, both with the active ingredient triclopyr, they are Ranger and Garlon. If the plant is cut back please ensure that all pieces are removed and destroyed as the stems of succulents typically take root easily when in contact with soil. If the roots are not removed, the cut stumps need to be treated with a suitable herbicide - Garlon and diesel should work.

Substitutes:The Port St John’s Creeper (Podranea ricasoliana) with its stunning display of trumpet shaped pink flowers is a good non-spiny alternative and so is the Hiccup Nut (Combretum bracteosum), also quite spectacular with its masses of bright orange-red rounded flower heads.