What is the best month to transplant perennials?
The recommended time for planting or transplanting perennials is late August or early September. This gives adequate time for roots to establish before winter comes. However, like most gardeners, I don’t usually think about it in late August and besides, this year was too hot to take on this task anyways. One rule of thumb is to transplant fall-blooming perennials in spring and spring-flowering perennials in fall. Knowing when to transplant perennials helps you avoid stress on the roots. Every time you dig up plants, some roots will be lost, so cooler conditions make fall transplanting perennials more successful.
What is the best time to cut perennials back?
Here’s how to cut back with confidence: Wait until after a few hard frosts. Once your perennials are fully dormant, it’s safe to remove their above-ground parts. Use clean, sharp pruners or shears. Don’t cut back evergreen perennials such as Kniphofia (red hot pokers), bergenias and heucheras. Simply remove any dead or tatty-looking foliage. You can cut back old hellebore leaves in late autumn, allowing the winter flowers to be seen better.