Although their name may suggest otherwise, perennial beds and borders do change with time. Every few years they need to be reevaluated. Plants may need to be moved to a different location where they will either look or grow better. A great number of perennials (at least the ones I grow) benefit from division. Perhaps those trees nearby have extended their branches enough to alter the amount of sunlight now available. Or maybe you lost part or all of a shade tree in last year’s wind storms. Maybe that cute little 4-inch pot of doronicum you planted has laid claim to more than its fair share of the garden. Even your tastes in colors, design ideas or seasons of bloom may have changed. Whatever the reason, spring is a good time to overhaul the perennial garden.

Elm broken by last year’s wind storm. Photo by dmp2020

Before you begin to pick up that spade and begin digging, you need to decide on the type of look you are aiming for. Your site conditions will likely dictate your choice of plant material. Try as you might, perennials like gaillardia, lavender and dianthus will not do well in soggy soils, while hellebores will wither away in hot, dry exposed sites. Consult one of the many splendid books or websites on perennials, talk to a knowledgeable person at a local garden center, or give us a call if you are in doubt about a plant’s cultural requirements.

Another factor to consider is the maintenance many perennials require for their best display. Delphiniums in all but the most sheltered areas need to be staked. Yarrows and evening primroses should be divided every couple of years. Garden phlox must be religiously deadheaded so its usually magenta colored progeny do not take over the world. Lilies need the once over just about every day to patrol for lily leaf beetles. And, some plants like columbine, rudbeckia and agastache just seem to have relatively short life spans, at least in my yard, and require regular replacement whether through self-seeding or store purchase. I don’t believe a plant exists that does not require at least occasional attention but if you are limited in the amount of time you have to deadhead, stake, divide, and control pests, you will definitely want to choose less demanding perennial species.

Birdhouse garden with desired coral colored phlox and self-seeded magenta phlox. Photo by dmp2009

When redoing your perennial beds, keep in mind also the season of bloom. Many perennials, for all their loveliness, have a tendency to bloom over a short 3 to 6-week span of time. A few will provide color, or at least interest from early summer until frost. These include plants like hostas, coral bells, Russian sage, and some dwarf daylily cultivars. Some gardeners strive for a riot of color for mainly one time period, say the month of June, while others prefer smaller portions of color that extend over the whole growing season. Spring flowering bulbs and annuals can provide interest either by complementing the flowers of perennials or as fillers when little else is blooming. 

Sedum, coral bells and artemesia provide a long season of color. Photo by dmp2012

Spring is generally a great time to divide mid and late season flowering perennials with the early fall being better suited for the early spring bloomers. If you cannot replant the divisions immediately, pot them up, or heel them in somewhere not in full sun. Perennials with a long tap root like baby’s breath and echinops do not appreciate being moved so place them carefully. Asters and some others in the composite family tend to die out in the center. Just transplant the new growth surrounding it and discard the woody middle part. If you need to move Oriental poppies, wait until they go dormant, usually in July or August.

Asters multiply quickly and benefit from division every 3 years or so. Photo by dmp2012.

Think about what bulbs you might like to see blooming with your early season perennials and make a note to purchase them for fall planting. Place the bulbs behind sprawling perennials so that the dying bulb foliage will be camouflaged.

Daffodils and other bulbs in the birdhouse garden and white garden. Photo by dmp2013.

Don’t be afraid to experiment and, most of all, don’t be afraid to rectify any unsatisfactory plantings. Unlike, permanent tree and shrub plantings, a perennial garden can be modified to suit your needs and desires.

Happy Spring!

Dawn P.