If you live in the UK and have some exposure to its property market, you probably would have come to know about Japanese Knotweed and all the hysteria that has been surrounding it. More specifically, the Japanese plant has been accused of growing through concrete and making the particular property not fit for sale, as a result. But is this really true or is it an urban myth? Keep reading to find out.
What is Japanese Knotweed?
You probably know what Japanese Knotweed is, but this is for the unawares. Japanese Knotweed is a flowering which was first introduced to the United Kingdom during the 1850s. Though there have been claims of the plant tearing through concrete and brickwork, the plant has been growing in UK gardens for years without causing major issues. The still intact roads and homes bear testimony to this fact. The plant grows a meter every month, invariably rising above native plant species and significantly impacting wildlife.
Does Japanese Knotweed Really Grow Through Concrete?
Plants can certainly break through concrete, but the concrete has to be of extremely bad quality for that to happen. The United Kingdom has been troubled a lot more by plants such as Buddleia, Ivy and Elder, than Japanese Knotweed. But no-one bats an eye when these plants play havoc and it’s always Knotweed that’s made the scapegoat. In fact, quite a few homeowners have no issues with other plants climbing up their walls. But if we had to understand why knotweed often gets blamed, then it’s probably due to its sheer presence.
For plants to physically grow through concrete is impossible. But Japanese Knotweed’s love affair with water and light and its constant yearning for the two, means it can easily exploit pitfalls in weakly laid concrete and break through via the mortar cracks, expansion joints, drain splits, etc. This means pavements and driveways could become uneven, walls may collapse, pathways could lift, drains would need replacement, fences will fall over or get pushed out, etc.
Homeowners usually find themselves locking horns with the plant, when they disregard a Knotweed-infested area and lay a surface such as concrete, patio slabs, asphalt, etc. over it. A surface paved with tarmac is definitely not going to prevent the plant from growing, especially if the surface is poorly laid. Similarly, Knotweed can easily disrupt brick set paving.
It’s not that difficult to excavate the ground and get rid of the plant and its traces. But the fact that it grows quickly, (even in areas which bore Knotweed root fragments), is what that makes eliminating knotweed extremely challenging. Moreover, many people don’t know that all Knotweed does not grow in the same way. The growth could vary, based on quite a few aspects such as the soil conditions, the presence of vegetation around and other nearby structures.
This is why some Knotweed excavations could be as shallow as less than a meter and then there are instances when the digging could run into several meters, just to take out one length of the rhizome. Thankfully, Knotweed rhizome can be easily identified, helping to ensure that only soil contaminated by Knotweed gets displaced.