I think it is important for the RHS to add a caveat about managing knotweed yourself; namely, if you plan to sell your property within the next 5 years, you should probably get it treated by a professional as otherwise you may find that mortgage lenders will not lend on the property, even for a small presence that is far from the building. We very nearly faced an intractable problem when selling because we had treated a small stand of knotweed for 3 years and none was present, but we weren't quite into the second knotweed-free growing season; we had to declare it as having historically been present as the freeholder of the property was aware of it and we felt we should anyway. Very fortunately, our buyer had encountered knotweed before and wasn't concerned and happy to take our word for it (plus it became apparent before exchange that we had got into a second season without regrowth). Otherwise we could have been in a catch 22 where the lenders would view us a being blighted by knotweed, but we wouldn't be able to get a guaranteed treatment from professionals because there was no knotweed to treat! So I think the RHS should highlight that homeowners should be careful of self treatment if planning to sell their home in the foreseeable future.