Lantana is very good at surviving attempts to get rid of it. Roots left in the soil will quickly regrow and green stems touching the surface will set root and become new plants. Even once an area is cleared, lantana seeds remain. If debris or other weeds prevent easy access to the site, those seeds will germinate and start reinfesting the site all over again.
Trial and error has taught us that the most efficient way to manually clear lantana is to follow a three step process. These steps minimise the amount of work involved and greatly reduce the time spent controlling regrowth
Step 1: Preparing to Clear
Herbicide use is critical in all weed control and bush regeneration. In areas of impenetrable lantana, glyphosate should first be applied to improve access and destroy viable lantana root systems.
There are two ways of doing this:
backpack sprayer, and
splatter gun.
A backpack sprayer is normally used in fairly small areas where the lantana is sparser and can be easily accessed. It is also the primary method of spraying in areas where there are native plants that we want to save. Unlike a splatter gun, a backpack sprayer gives much greater control over where the Roundup goes. When a shroud is placed on the spray nozzle, a backpack sprayer can effectively put Roundup on weeds that are close to small native plants and newly planted trees without risking it drifting onto their leaves.
A splatter gun works by using pressurised gas to propel highly concentrated Roundup over a large area. This means that it can reach far deeper into a lantana thicket than would be possible with a backpack sprayer. Depending on the pressure used, a splatter gun has a range of up to 10 metres. Adjustable nozzles on some models of backpack sprayers allow them to double as splatter guns.
Because glyphosate kills everything in range, we generally only use it when there are very few native plants growing under the lantana. Experience has taught us that native seedlings grow really fast once exposed. If sprayed as part of the lantana control, they have to be replaced by new plantings. This takes time and incurs unnecessary costs.
About three months after the lantana has been sprayed, it is ready to be pulled out.
Although the lantana will appear completely defoliated around one month after being sprayed, the stems will still be green and the roots will still be well anchored. Glyphosate does not reach its full effect until two to three months after being applied. By this time, all the stems that were going to dry out will have done so and the root system will be significantly weaker.
Now it is time to move on to Step 2, lantana removal. It is very important not to take too long getting to Step 2. After a few more months, some of the lantana will start to regrow and, if left unchecked, will steadily re-infest the site. This is because glyphosate does not always kill the entire plant and does not prevent lantana seeds from germinating.
Step 2: Clearing the Lantana
Digging stump with mattock
1. Aim for the stumps
The easiest way to clear lantana is to get at its stumps. If you can reach the base of the plant, you can cut off the stems and pull them out of the thicket one-by-one. After the stems have been removed and the stump fully exposed, it can be dug out with a mattock. If the stump is too big to dig out and is still green, paint undiluted glyphosate onto the cut surfaces.
In many cases though, the lantana plant will be loose enough to simply pull out without needing to be cut or dug up.
Cut section reshooting
2. Avoid mashing up lantana stems into little bits
It is much quicker to pull whole lantana plants or to roll whole walls of lantana that than it is to hack them up into little bits before trying to remove them. We generally favour brush axes and large loppers for this purpose. Lantana should never be cut into small sections while green as they will regrow.
3. Sometimes hacking is the only way to get to a stump quickly
This is a very important point to remember. When a thicket is just too dense to effectively get at with loppers and saws, it is time to bring in the hackers. We use brush axes for this purpose. They are lightweight and have a curved steel blade at the end of a fibreglass handle.
We call this part of the process ‘hacktivism’. The goal is to get to the stumps and cut the stems into manageable sizes. We still want to avoid mashing the lantana into little pieces if possible. 4. Pull out all the roots
There are always some lantana roots left in the ground after pulling out or digging up a stump. These must be removed or they will reshoot. Usually they can be pulled by hand but will sometimes require a mattock. To check that all the roots have been pulled, we generally run through the leaf litter with our boots in order to expose any stragglers.
Lantana piles
5. Pile up the lantana while keeping roots off the ground It is often tempting to just drop lantana where it is pulled or trample dead lantana without going to the effort of pulling it out and piling it up. While this is easier, we have found that it is not as effective for a couple of reasons.
First, having stems lying all over the ground makes it harder to walk on, harder to control other weeds and harder to gain access to plant new trees. Second, it is too easy to miss roots and small stumps.
The solution is to make piles of lantana. These decay fairly quickly and also make it much easier to manage any regrowth. The only thing to remember here is to keep the roots off the ground. If any roots are touching the soil, they will probably regrow.
6. There will be collateral damage You cannot make an omelette without breaking eggs. So it might be said that you cannot rehabilitate a site without damaging some native plants in the process.
Collateral damage is just a normal part of lantana control whether it be accidently spraying natives or accidently chopping off or trampling a native plant while removing the lantana. The message here is not to obsess over saving every single native plant as part of the broader goal of rehabilitating a site.
At the same time however, we do try to avoid collateral damage if possible. We just make sure that this does not slow down our progress towards the main goal of making a site weed-free.
Step 3: Follow up
Follow-up generally involves walking over a cleared site to check for any reshooting roots, stems or seedlings.
Flag any native seedling with marker tape or with tree cages. This reduces the risk of accidental spraying.
It is generally best to do follow-up every two or so months after a site has been cleared. There should be less and less lantana regrowth each time. When the amount of regrowth is negligible (think 10 new shoots per acre or less), the site will only need lantana follow-up occasionally. Most newly cleared sites reach this maintenance point after about one year. From there, we do follow-up approximately every six months.
If piles have any regrowth that cannot be easily pulled out, spray them.
Annual weeds such as cobbler’s pegs, stinking roger,mustard, fleabane, inkweed and thistles often rapidly repopulate a cleared site. When this happens, it is generally easier just to use the backpack sprayer with a selective herbicide such as dicamba/MCPA (ie weed'n'feed) to elimintate them without impacting native grasses.
One final tip. When doing follow-up, don’t forget took look up the trees as well. It is truly amazing how often a single stem goes unnoticed simply because it is above eye level!