It’s easy enough to list the things we Australians DON’T like about that invader from South America, Lantana camara. Alas, that we inflicted it upon ourselves, with our careless gardening habits!
1. It colonises disturbed soil with dense shrubbery, 2-4 metres tall, crowding out smaller plants and preventing regrowth of native trees.
2 As the native vegetation is lost, so is the wildlife that depended on it.
3. Lantana behaves as a nurse plant to privet, an even worse, tree-sized weed, enabling it to establish a virtual monoculture on what was previously rainforest land. The privet forest on the Eastern slopes near Toowoomba, is a classic example of this.
4. Lantana has huge economic impact, reducing the productivity of pastoral and forestry land.
5. Its leaves are poisonous to stock, (some varieties more than others).
6. It’s a prickly, scratchy nuisance to bushwalkers.
Lantana has some Good Points Too
Whenever a super-weed like lantana creates a new
environment, some native animals will find a niche to their liking, and
1. Small birds like wrens find lantana thickets an ideal place to live, eating the succulent fruits, and building nests in the scratchy thickets.
2. It shelters small mammals, such as antechinus, bush rats, and bandicoots.
3. Reptiles, especially small skinks, make use of the shelter.
4. Butterflies love the nectar-rich flowers, which provide them with food over a long season (albeit while slowly exterminating their species by crowding out their host plants).
5. The pithy stems are used as homes by the primitively-social reed bees (Exoneura species). These bees are important pollinators of native plants.
6. It improves soil quality, and controls erosion on slopes.
Does this mean we should love lantana, after all?
Well, no. Not really.
A natural mixture of native plants is the basis for a richer, more varied ecosystem. It hosts more kinds of birds, mammals, reptiles, and insects than lantana ever could, and stabilises the soil just as well.
But lantana’s good points can be a reason for avoiding the “bull at a gate” approach to removing it. We have to keep in mind that clearing weeds is not a beneficial environmental activity in itself. It’s what comes after the clearing that matters. If no thought is put into where they are to go, those little creatures which managed to make lives for themselves among the weeds, then clearing them only causes a net loss of biodiversity.
“Softly, softly”, is the answer.
If we’re hoping that natural regeneration of plants will provide for the displaced wildlife, we need to clear in small doses, and monitor whether regeneration, of the kinds of plants we were hoping for, is really happening.
Were our expectations unrealistic? If clearing doesn’t result in a cheering surge of new growth - and it often doesn’t in our dry and erratic climate - then active revegetation is needed. Plants must be planted, and tended until their survival is assured, and meanwhile, the cleared area will need constant weeding of lantana (and other weed) regrowth so the carefully-planted seedlings aren't lost to shading and root competition. Too many bushcare projects have been sent back to square one by lack of follow-up!
Working with nature is the way to go, when revegetating. A half-and-half approach, blanket planting planting pioneer species to modify the environment, can provide both fast shelter for wildlife and a suitable mileu for natural regeneration of longer-lived species. This only works if there is a natural seed source nearby, of course. Revegetation of rainforests and scrubs, on the other hand, can be slowed down by mistaking fast-growing dry sclerophyll plants such as wattles and eucalypts for pioneers, though. These greedy plants rob the soil of moisture, slow down the growth of other plants, and simply establish themselves as the dominant vegetation.
Sometimes, the best approach to clearing lantana consists of leaving it alone for a few years, and getting on with planting, instead. Once refuges for wildlife have been established, the clearing can go ahead - but always in proportion to the shelter available.
Now is the time to be planning it. The frosts will be over before very long.