Every year, gardeners have to deal with perennials that outgrow their intended home. There are a number of solutions that will improve the look of your landscape. Many of us simply cut back the plants that have exceeded the growth that we desired. Prune branches off flowering shrubs or those perennials that line walkways, the driveway or other areas more because they are in the way of pedestrians, cars and lawnmowers. This is sometimes still the best solution and one that I still use with hardy mums and my butterfly bush, because in the end it is best for the health of the plant in question. It is important to know when each plant should be trimmed before getting started because cutting too soon could result in lost blooms or growth.
Another easy solution involves simply expanding the garden bed that houses the overgrown perennial. You can remove a strip of grass around the bed or just on the side in need of more room to give everything more room. This is helpful with garden beds that have become overcrowded or are out of room for low growing border plants, which you can now plant where the grass was removed.
You can also tame perennials with a tendency to become overgrown in clumps by dividing them and either planting the sections you remove elsewhere in your landscaping. You could also give the extra plant sections away to friends or neighbors, particularly if you are completely out of space. Some plants, like the bearded iris, really benefit from being divided up on occasion. Each smaller clump will be healthier, bloom better and take up less space than the larger clump they originated from. The iris clumps can triple in size in a few years, which can crowd out other plants or pushing the boundaries of their garden bed.