GET PLANTING NEW PERENNIALS

HARDY perennials, such as heleniums (pictured), are selling fast. Plant up as soon as you can.

If the roots are congested, when you remove the perennial from its pot or liner, tease it out gently.

It helps to mix a little bone meal or slow-release fertiliser into the planting hole — but use it sparingly. Firm the plant gently into place and water during dry periods until the roots are established. Make sure your purchases are fully hardy. You can check in a reference book or at rhs.org.uk. Hardy varieties are safe to plant and leave unprotected. Borderline tender plants such as penstemons, osteospermums or New World salvias need protection if frost is forecast. But they should be safe after mid-May.