By definition, perennials last year after year, providing colorful flowers throughout the season and healthy foliage throughout most of the year. When properly maintained in a suitable climate, they’ll flourish in containers for 5 years or more before you’ll need to move them into open soil.
Select a container about twice the size of the nursery pot, keeping in mind that, with proper care, a healthy and maturing perennial likely will need transplanting at midseason to provide it necessary room for root growth. It will also require transplanting again in the second year.
Photo Credit: ©2000 Dolezal Publishing/Kyle Chesser
The roots of most perennials spread wide and deep, making them distinctively different from annuals and bulbs. In a container, this tendency requires a watchful eye and a commitment to pruning, repotting and dividing to control growth and give the plant proper room to thrive. It’s a good rule to limit planting to one or two perennials per container, or you’ll soon find yourself dividing and repotting. (If your heart is set on multiple perennials in a single planter, choose a pot that’s at least 24 inches in diameter, and expect to repot or divide your plants every year or two.)
By their second year, most blooming perennials burst with color that can last weeks or even months. Prune back the plant just after its bloom to promote more prolific and compact blooms in subsequent years.
Because container plants are more exposed than those growing in an inground garden, potted perennials won’t survive severe cold, so you must protect your potted plants (or overwinter them) during their dormant months. This helps protect their root systems and latent buds from damage due to freezing. A cool space is best, and even a deep, covered porch close to the house may be adequate in mild-winter climates. Remember to water dormant plants during winter whenever their soil dries.
Dormancy is also the best time to repot perennials. Use a sharp trowel or knife to divide the root masses into smaller clumps. Use standard potting mix with a good dose of sand and perlite to help drainage, then replant each root division in its own container before watering thoroughly.
Perennials have extensive root systems compared with annuals – roots that require protection and care during transplanting. Each time you find your healthy perennials on the verge of outgrowing their container and in need of the elbow room afforded by a new, larger pot, transplant them by taking the steps shown in the following pictures and described in their captions.
Planting Perennials in Containers
Planting Perennials in Containers - Step 1
Select and
clean your container. Cover its drain hole with wire mesh and fine gravel or other drainage medium. Add about 3 inches of moist potting soil to cover the bottom.
Photo Credit: ©2000 Dolezal Publishing/Kyle Chesser
Planting Perennials in Containers - Step 2
Mold the
potting mix to the container sides with your hands, creating a bowl for the plant’s deepest roots.
Photo Credit: ©2000 Dolezal Publishing/Kyle Chesser
Planting Perennials in Containers - Step 3
Invert and gently ease your plant out of its nursery container. Avoid using a trowel to loosen the plant, as you might damage sensitive roots.
Photo Credit: ©2000 Dolezal Publishing/Kyle Chesser
Planting Perennials in Containers - Step 4
Loosen the root ball where roots encircle the plant or are matted. Place the plant in the new container with the top of its root ball slightly above the soil surface and just below the container’s rim.
Photo Credit: ©2000 Dolezal Publishing/Kyle Chesser
Planting Perennials in Containers - Step 5
Backfill the container with potting soil. Compact the soil gently to stabilize it. Leave the top of the root ball slightly exposed, with the plant at its original level.
Photo Credit: ©2000 Dolezal Publishing/Kyle Chesser
