Well, here we are and it is already Fall. Where did spring and summer go? Soon I'll be wondering what happened to my 40's...I spent them gardening!
This is really the best time to split plants and move them around.
My Black-eyed Suzans are growing out of control and need to be split before they start to over-shadow other plants and impact the positive growth of other plants. So now is the time that I cut them down and seed out the seeds in a few places. I also dig up and split the growth that is intruding on other plants and move them to areas of my garden that needed some more late summer color. Because we all know that they have great foliage and awesome late summer appeal.
Evening primrose is definitely another plant that needs to be taken care of. I usually have to dig it out of my beds and just leave a few small areas intact...it spreads like an invasive but is luckily fairly easy to pull out. It can also be spread to other parts of the garden. I'm one to battle invasive against invasive so next year I'll be putting it with my evil snow on the mountain...yes I have some...don't put it in your garden...but since it's already in mine I thought I would see how these two hold up together.
I also want to say that some of my grasses are getting kind of large. I'm going to wait till spring to split, though, as I find they make a nice place for critters to overwinter.
Perhaps you did not like what was happening in some part of the garden and you want to move plants to a different part of the garden. For example you may have to move some taller plants to the back of the bed because it covered up some shorter plant. It happens, this is the time to do it!