Hardy Hibiscus has skinny stalks
I have had a hardy hibiscus for about 6-7 years now. In past years it has done beautifully prospering and growing. In previous seasons the stalks have been about 2" wide. I cut them down at the end of the season. In most years when the pieces left above ground dry out sufficiently, I can pop them out to leave room for the next years growth. Last fall I did not get a chance to do this and had an early spurt of spring growth so they stayed there. This was never a problem in the past.
I keep a wire fence about 3' tall around the plant to support any drooping stalks. This year I have had incredible growth and my plant is already 5'+ tall. The problem is that its stalks are only 1/4 to 1/2" and cannot support the growth. My little fence is not doing the trick. I tried bracing them up by looping some twine around the stalks but I am afraid that I am cutting off the air circulation that they need.
What can I do? Should I cut the whole thing down and sacrifice the flowers? Should I take it up and divide the plant? Are the skinny stalks caused b/c it has gotten too big? How much room do the roots need around the base of the plant. The particular flower bed they are in is approx 12x8. The peony next to it did not flower this year because I pulled out some overgrown daylillies. Could this affect the stalk size also? There is planty of space between the plants but I am wondering if the root systems are starting to fight each other. I appreciate any advice you have. Thanks.