OK, can I just say this? Never, ever plant Fallopia japonica var. compacta, otherwise known as Japanese knotweed. Ornamental groundcover, my eye.
I guess that technically, it does have pretty green leaves and pretty though somewhat insignificant spikes of white and pink flowers. And yes, it could be termed a groundcover, as in it seems bent on taking over and covering my entire yard. However, groundcovers do not, in my book, grow to be three feet tall. That's a shrub, folks.
The former owners of my house, in their zeal to landscape the front yard, planted NINE of these demon-spawn plants. They started out in 8-inch pots...I can tell this because you can still see the outline of the garden-center soil in the ground.
I have spent many hours over the past few days trying to pull up, dislodge, and otherwise eradicate these plants. They are crowding out all the other nicely behaved plants in the beds, like lavender, oregano, rosemary, and hydrangeas. They spread out from their 8" starting points literally 6 feet in every direction. And three feet tall. Did I mention that? Shading out the neighbors. Just cutting them down does absolutely no good, because they spread by underground runners. The tiniest piece left in the soil will give rise to a whole new plant. Pulling up the runners causes their well-behaved neighbors to come loose as well. The new growth on the end of the runner is brittle and breaks off with the slightest tug. The older runners are so woody and tough that it's almost impossible to break them, and they go not only sideways, but down, so that they're almost welded into the clay soil that is under the top layer of my yard.
Emma did think it was funny this morning when I sat down hard after a root broke unexpectedly. "Mama go boom! Hee hee hee hee! Boom!" Just wait until you're older, girlie, and can be put to some serious child labor...
I harbor no illusions that I got all the pieces of roots of the six I have dislodged so far. I'm going to be pulling up this plant forever.
Why, oh why do evil nursery folks even sell this?