But!! I probably over amended my planting soil when I planted them. I knew at the time that grasses like a lean planting mix, but I was dealing with a clay gravel situation that I literally used a pick axe to dig the planting holes. Deciding nothing will grow in this, I disguarded this clay/gravel and planted in a top soil mix. The growth on these plants is so prolific that one rain and they are on the ground.

Apart from removing them and de-amending?? the planting soil with a leaner addition like sand or gravel and replanting, is there anything I can do??

I have read that perrenial flower growers often cut back perrenials that would get too tall and require staking. They still flower but smaller blooms, not as many blooms and the plants are shorter. Would this work with grasses?

Any suggestions will be appreciated.

Thanks
Phil Little

First, your zone is at the bottom of Panicum's hardiness range. Even in full sun, your growing season may not be long enough to fully support the plant.

Second, you mention you water "sparingly, if at all." Panicum does best in medium to moist conditions.

Cutting the grasses back before blooming is not an option. You'll end up with square-ended blades, which will continue to grow, and develop browned square tips.

Re-doing the soil and replanting the sweep will be terribly labor-intensive. I'd suggest trying something else. Get some netting of some sort. Farm supply firms sell 6" square polypropylene trellis netting, used for growing pole beans and other vining species. You can install this horizontally, supported by stakes, and force the grass to grow up through it. As the grass grows, the netting will disappear, but still provide support. Chances are a single layer, about 2 feet above the crown, will suffice, but you may want to go to a second layer as well. Be sure to stretch the netting taught and use plenty of support stakes. Don't bother trying to get the edges of the planting under the netting. Just trim away any blades/culms which flop around the edges. As long as the majority of the planting is supported, it will look great.