Q.Miscanthus
We have 3 plants in our garden. I have just noticed what looks like small but new thick stems of knotweed growing in the middle of all 3 and at the side but close to the existing shrub. Could these simply be new stems as I can’t believe that knotweed has suddenly decided to grow in 3 plants all in a completely different area. I have googled new stem images of miscanthus and they do look very similar to knotweed. Hope you can help.

Certified GKH Gardening Expert
Do you mean nutsedge or crabgrass rather than knotweed, because miscanthus does not look like knotweed. Miscanthus would be coming in the center and right at the edge of the clump, not usually away from it. But other grassy weeds such as nutsedge or crabgrass might. It is probably your miscanthus returning, so I would let it grow until you know for sure.
https://www.gardeningknowhow.com/plant-problems/weeds/controlling-sedge-weeds.htm
https://www.gardeningknowhow.com/lawn-care/lgen/lawn-weed-identification.htm