Marloth Park Management Plan. - Nkomazi Local Municipality

Ricinus communis, Solanum sisymbriifolium and Xanthium strumarium
The castor bean Ricinus communis (Category 2) can be recognized by its large shiny palmate
(hand-shaped) leafs. The wild tomato Solanum sisymbriifolium is also a noxious weed
(Category 1), but recognized by it prickly appearance. The large cocklebur Xanthium
strumarium is characterized by it profusion of spiky seedpods, and due to its invasive
properties classified as an undesirable weed (Category 1). These species can be found
distributed throughout Marloth Park, but nowhere in large densities. It is, however,
recommended that all these species be mechanically removed when encountered. The castor
bean and the wild tomato are relatively low priority species, but wild tomato and large
cocklebur should be considered high priority species that must be controlled.
Alien species
There are a myriad of other alien species found on Marloth Park, many of these considered
naturalized weeds or acceptable garden plants. Undesirable weeds such as Amaranthus sp.,
Bidens pilosa and Tagetes minuta are all considered low priority plant species found
throughout Marloth Park. These plant species are usually associated with disturbed areas such
as roadsides. Control of these plants can effectively be obtained by a natural burning regime,
as the application of herbicide, although effective, is not considered economically viable.
BUSH ENCROACHMENT
Bush encroachment is commonly defined as an increasing woody plant density. With the
woody plant component increasing the grass sward diminishes, as the woody seedlings out
compete the herbaceous layer for water supplies. This causes a decrease in an areas´ grazing
capacity. Effects of overgrazing become more and more severe.
With an increase of the level of tree thinning more and more grasses colonize bare ground.
With less competition from woody plants for ground water after tree thinning, grasses stand a
better chance to establish. To promote grass production in the areas of arid mixed bushveld no
more than 1500 to 1700 trees per hectare are recommended This recommendation represents
an approach between positive and negative interaction of trees and herbaceous layer as well as
the aridity of the area as it influences the available soil moisture. The desired vegetation
structure is an open savanna, which consists mainly of large trees, interspersed with relatively
few small trees.
© Ecological Associates/ Marloth Park 96