Stymie those unwanted weeds
Weeds tend to run rampant at this time of year.
An effective chemical-free way of keeping invasive weeds under control in open areas of garden is by using weedmat.
A woven plastic mat, weedmat on the soil surface provides a barrier to most weeds, with the exception of one or two types of grasses. Because the mat is woven, it allows moisture and some water-conveyed plant foods to pass through to the soil below.
It also allows the soil to breathe, preventing an anaerobic situation occurring.
Pre weedmat, sheets of black plastic film were laid down and were covered with material such as scoria (reddish volcanic rock). The soil underneath became oxygen deprived, and over time, the oxygen starved soil became anaerobic, with any plants growing in it eventually dying. A great improvement on plastic film, weedmat only works in one direction, preventing weeds from growing upwards.
It’s not a foolproof solution, however. Weed seeds can germinate in whatever medium covers the mat, and their roots will penetrate the mat downwards. The plus is that these are easy to pull out as they cannot easily establish a secure root system.
Weeds will also appear where the mat has been cut to allow preferred plants to grow. As it’s not always easy to fit snugly around established plants, it may pay to overlay cuts and holes with offcuts to minimise weed germinating opportunities.
Weedmat is also remarkably longlasting. Covered with bark or stones to prevent exposure to UV, weedmat could last in the garden for 25 years or more.
But do be careful about what you use to cover the mat. Foraging birds will flick any lighter material off, so use bark nuggets (large bark pieces) or suitable stones as cover.
For vegetable and flower beds, however, weedmat is not so practical. So, to discourage weeds in these plots, place layered sheets of soaked newspaper or cardboard on the soil and cover with a purchased (weed-free) compost.
This will create a temporary weed barrier while seedlings can be planted
directly into the covering compost.
There are plenty of advantages to using cardboard or newspaper as worms love it, moisture is retained better, and carbon is returned to the soil.
For invasive weeds such as convolvulus or twitch (couch) grass perennially coming through from next door, the only long-term solution is to dig a trench along the fence line about 20 to 30 cm deep and line the fence side of the trench with sheets of galvanised iron. Back fill the trench so that the iron is buried deeply in the ground but protruding a few cm above the soil level. Cap this with wood or old bricks to reduce the chances of hands or feet being cut on the exposed edge.
If you can’t get the iron flush with the fence, simply pour salt into the gap whenever a weed appears. Salt is also an excellent way to control weeds growing between pavers or in cracks in drives or paths.
The white triumphant trumpets of the prolific invasive weed Convolvulus arvensis. Control is possible in certain circumstances.