|Photo by Jamie|
I first noticed it around the edge of our flower garden that was created with a sheet of black plastic. Black Plastic was put down till the grass died and then I ran timbers around the rectangle shape of the space created. I didn't run the timbers right to the edge and left a bit of bare ground just outside the timbers. Inside the area framed by timbers, I scratched the ground and broadcast some perennial flowers and those came up along with other wildflowers. No where on the interior of this garden space did Gaura Biennis grow. It only grew, and quite thickly, right along the outside edge of the timbers where the grass had been killed but the earth not scratched. In this area it was dense, healthy and grew about 6 feet tall in the full sun. I've read it likes shade, but it did great in the full sun.
The other areas it grew last year were a few places that were mowed the prior fall and winter and then left uncut in the spring. This year almost none is growing on the bottom land even though it went to seed because I didn't mow down there last fall/ winter.
This year, it's growing like crazy on the hill around the edge of a burn pile. It's not growing in center of the old burn pile, but only along the edge right where the grass and burn area meet. In this area it's growing thickly and is tall. Just out from that thick growth a few are growing here and there where the grass was cut in the fall, but it's much shorter.
I'm going to try to get it to come back near my garden next year by mowing around the garden this fall and laying down cardboard or old cotton clothes till the grass dies. Then I'll pick up the cover and just leave the area alone. I hope that does it.
This is a wonderfully beneficial plant so I've really been paying attention to how to get it back! To see plants that would be attacked by the Japanese beetle if Gaura Biennis wasn't around, see the "Host Plants" section of this Wikipedia article.
I may have mentioned this before, but I read that if you remove OVER 50% of the Japanese Beetles, as a group they will all move somewhere else (like to your garden). It's very easy to reduce the Japanese Beetle population by getting a jar of water with a little soap in it. Then hold the jar right below the beetle and tap the branch it's on. They fall off very easily. I was careful just to remove some to reduce the population, but not to remove all. Like I mentioned in a prior post, the Guara Biennis was hanging over the garden with Japaense beetles all over it and there were none in the garden. If they fell off, they got right back the Guara and stayed out of the garden.