This is a great way to maintain the vigour of perennial plants and to increase them. At this time of the year, many perennial plants such as asters, columbines, day lilies, phlox (pictured below) and many others will be losing their foliage and can now be carefully lifted and divided. First, start by lifting clumps – many will have fibrous roots and will need to be replanted straight away. You can pot some into pots of compost and plant the others in the border with some fresh compost.
In the past few years, I have doubled and trebled the number of plants in my garden. I label everything to keep track of what’s what.