Perennials.
Perennials are the largest group of garden plants and offer magnificent diversity for every location from sun to shade. Plants range in size from ground-covering and clump-forming varieties just a few centimetres high, right up to statuesque giants a couple of metres tall. Growth is quick and most plants reach a mature size within one or two growing seasons. Perennials mostly flower in spring, summer or autumn, with a handful blooming in winter, and many have attractive foliage too.
Most perennials are herbaceous, meaning they die back to the ground in autumn and regrowing in spring. However some are evergreen and keep their leaves all year. Many perennials make good cut flowers and the more compact varieties that have long-lasting appeal are excellent for growing in pots. In borders, perennials combine well with shrubs, conifers and ornamental grasses to make attractive displays that give long-lasting interest.
Planting.
Prepare ground thoroughly, as some perennials will be there for years. Improve soil with plenty of well-rotted organic matter or soil conditioner, remove large stones and clear all weeds, particularly the roots of perennial weeds.
Dig a hole slightly larger than the plants’ roots or pot, take off the pot and carefully unwind any roots that have spiralled around the rootball. Put the perennial in the ground so the top of the rootball is at soil level, backfill with soil, firm to remove any air pockets, and water thoroughly.
Caring.
In spring or early summer, support tall-growing perennials with stakes such as canes and string, or grow-through plant supports placed over the clump
Through spring and summer, keep the surrounding ground clear of weeds
Remove dead and faded flowers to prolong the flowering season and to keep plants looking good
In autumn, cut back fleshy-leaved perennials as soon as they die back, otherwise the leaves go soggy and rot
Woody-stemmed perennial growth can be left until late winter/spring before cutting back. Frost, mist, and snow transform parchment-colored stems into a winter wonderland, and during very cold winters, this growth also helps protect the roots from damage by severe frosts. Beneficial insects such as ladybirds hibernate in dead stems
Tidy evergreen perennials from time to time to remove dead or tatty leaves and faded flower stems
After three to five years, perennials tend to form large clumps and performance starts to decline. Lifting, dividing and replanting them will rejuvenate plants and provide you with more plants to grow around the garden
Propagating.
Perennials are superb for the budget-conscious gardener. Many can be raised cheaply from seed, then, once perennials have formed good-sized clumps, nearly all can be propagated by division, breaking up the clump into good-sized chunks to replant while discarding the old, woody center.