Conservation

For up-to-date news, activities and calendar of events please visit www.crocodileriverreserve.co.za  

This biodiversity stewardship project aims to provide formal conservation protection for the area of the Rhenosterspruit Nature Conservancy, and beyond. 

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How to deal with Pom-Pom, Lantana and Syringa

The City of Tshwane has, in conjunction with DWAF and GDACE published an information leaflet.

In this leaflet we are very clearly informed that it is a violation to

a) have invasive aliens growing, and

b) to neglect to implement a program of irradication.

Where, what and how? Which plants are invasive aliens?

The plants are divided into Categories, each with a specific action required.

Category One Weeds

You may not have these plants on your property, and you must be able to show how you are dealing with eradication.

Fines of R10 000 and/or 4 years jail time apply.

Plants:

Lantana, Pom Pom Weed, Budweed,Azolla, Queen of the Night, Pampas Grass, Cat's Claw creeper, Red sesbania, Olenader, Yellow bells, Water hyacinth, Balloon Vine

Category Two Weeds

These are invader plants that pose a threat to the enviornment but can be exploited. These species are only allowed in demarcated areas. If you have them, you need a water use license from DWAF as these plants consume large quantities of water. Outside of demarcated areas, these plants have to be controlled.

Plants:

Black wattle, Patula Pine, Sisal, Red eye, Grey poplar, Watercress, Blue gum, Cluster pine, Honey locust, Weeping Willow (not to be confused with indigenous willow)

Category Three Weeds

These are plants that have the potential of being invasive but are considered to have ornamental value. If you ALREADY have them, you have only to control growth, and spread is not allowed. No new plantings may take place, and plants may not be sold.

Plants:

Syringa, Lacaranda, Australian Silky Oak, St Josephs Lily, Sword Fern, Tipu Tree, Privet, Monring Glory.

What to do

For the plants most commonly occuring in the RNC - the pom pom weed, the lantana and the syringa, we share the experiences of landowners.

Pom-Pom Weed

The pom pom weed is particularly hardy and adaptive. In the first year of the project, the heads of the flowers were cut-off to minimize spread, while a process of manual removal began.

It was found that vigorous leafy growth, and multiple new flower heads formed where the flowers were cut off. Without an aggressive eradication program alongside the removal of flower heads, the spread of pom pom is enhanced rather than limited.

Do no cut the flower heads if you are not following through with eradication.

Manual removal required that the entire plant be dug out, and burnt. The pom-pom grows, and spreads, through the rhizome (underground root). Cutting the plant at soil surface (such as with a tractor or weed-eater) causes a spurt of growth underground and rapid multiplication. The same effect occurs if the plant is burnt while rooted in the soil. It was reported that the plant becomes diminished through frequent cutting. This has not been our experience. The cut plants grow vigorously, and tend to be shorter. This makes them more difficult to locate in among long grass, and the spread is as vigorous.

If the plants have been removed they MUST be burned. Even leaving the removed plants to decay causes the release of a chemical. This chemical adds to the destruction caused by the pom-pom. Whether in the ground or removed, the chemical prevents other plants from germinating. Over time, the pom-pom is all that remains and valuable grassland and fodder are eradicated.

The most effective method of control has been an approved herbicide. In this project the application of herbicide over three years has significantly reduced the number of pom-pom. However, the plants appear to adapt, growing shorter. As they are more difficult to locate, the need to be vigilant is as great as before. Adjoining properties left unattended have also curtailed the effectiveness of the spraying program.

It is also imperative to continue to spray throughout the growing season. Why? Well this plant is so well designed to propagate itself that young plants continue to come up until about April. You may kill off the "grandparent" but by the end of the season there could be as many as 4 "generations" in the same vicinity. Patrol regularly, and catch the plant before the flowers start for best results.

The herbicide used is Access.

Lantana

Lantana is a shrub with attractive multi-coloured flowers. The flowers can occur in shades of pink or of orange.

Left undisturbed, the shrub can grow tall and lush. It is best to intervene while the plant is young. It is deeply rooted so take great care when removing manually.

Access herbicide used for pom-pom is effective on the Lantana too.

Syringa

While the adult trees may be left in place, the control of new plants is imperative. The syringa spreads quickly and widely. Even small saplings will have a deep root, and cannot easily be pulled out (successfully) by hand. A young sapling sprayed with Access, is quickly dealt a mortal blow.

Older plants can be cut down, and Access applied to the cut area within 30 minutes will ensure no further regrowth takes place.

Young trees as tall as 2 metres have been effectively treated with herbicide applied to the leaves. The tree has died within 3 weeks.