What is giant knotweed and hybrid knotweed?

Giant knotweed is similar to Japanese knotweed, but as the name suggests, much larger in size. Giant knotweed can grow to more than 4 metres in height and its leaves can span around 20-40cm, and roots which can extend to depths of 2m.

In the Spring, reddish shoots emerge and begin to grow rapidly, reaching heights of around 4m by the Summer, when flowers, of white with a green tinge, will appear in amongst the dense foliage. In the autumn, the foliage begins to wilt as the leaves turn yellow. By Winter the plant above the ground will be reduced to pale hollow stalks that can take 12 months or more to decompose.

A Japanese knotweed and giant knotweed hybrid called Fallopia x bohemica can also be found in the UK. This grows somewhere between the 2.5 – 4 metres. The leaves are larger than Japanese Knotweed but smaller than giant knotweed, and it has flowers of white and cream with a green tinge. The leaves can also vary in shape from square ended to heart shaped and both variations can appear on the same plant.

• Where does it come from?

Originally from Japan, China and Taiwan, they escaped from ornamental gardens, and have become established across the UK.

Can I make a claim if giant knotweed and hybrid knotweeds encroach upon my property?

If you have purchased a property that has an infestation of Giant Knotweed & Hybrid Knotweeds that wasn’t picked up on your professional surveys when you acquired the property, you may be able to make a claim for professional negligence against the surveyor.

If you have noticed Giant Knotweed & Hybrid Knotweeds on your land, the origin of which is coming from a neighbour’s property, you may be able to recover compensation for any loss in value of your own property that is sustained. You may also be able to obtain a Court Order which specifies that your neighbour must put an appropriate treatment order in place.

Depending on the extent of the problem, the costs of this could run into thousands of pounds. The steps to remedy the issue may need to take place on your property or on neighbouring land.

If your property has been damaged by the giant knotweed and hybrid knotweeds, you may be able to recover the costs of the repair work to the property.

In severe cases, your property may have lost value due to the presence of the giant knotweed and hybrid knotweeds. This is called diminution. Subject to appropriate evidence being obtained from a specialist, you may be entitled to recover the cost of this diminution.