I have bought perennial plug plants, which I intend to bring on in pots. When they have matured somewhat, do I overwinter them in the greenhouse or plant them straight out into the border, say in October? Regards, Glyn.
Certified GKH Gardening Expert
Perennials can be planted in early fall, but the earlier the better, unless you live in a warm climate with very little frost during the winter. The reason is that you want the plants to establish strong root systems in the ground before frosts begin.
In a colder climate, you could overwinter your perennials in the greenhouse or in a dormant form depending how big they are, then plant in early spring. But the best option is probably to plant them now and cover the roots with mulch, and perhaps a cloth cover over all of them: