How to Prune a White Swan

Prepare a 10 percent solution of chlorine bleach in a spray bottle; mix one part bleach with nine parts water. Spray the blades of bypass pruners with the disinfectant bleach solution before pruning the coneflowers.

Remove all dead plant material in early spring before new leaf growth begins. The dead parts might pull away easily in your hands or even crumble. Use the bypass pruners to cut the dead stems back to the ground if you can't remove them by hand.

Cut back some of your white coneflower plants to half their height in early summer before blooming begins. This step is optional, but delays blooming to ensure a flush of blooming in fall. You might decide to dedicate one patch of white coneflowers to midsummer blooming and cut back another patch to guarantee a fall bloom.

Cut stems back to the nearest leaf set to deadhead the flowers as soon as the flowers begin to expire. This prevents the flowers from going to seed early and encourages the plant to divert its energy toward new flower development. Plants usually start flowering in mid- to late June or early July depending on the hardiness zone. Expect later flowering in northern climates.

Cut the plants back by about one-third of the total height when flower production slows. Use bypass pruners if you only have a few plants, or use hedge shears for a large plot of "White Swan" coneflowers. This type of pruning fixes legginess in plants and often results in a second flush of blooming that can extend into fall. If the flowers bloom a second time, deadhead the blossoms as they expire so the plant keeps producing new flowers.

Stop deadheading the coneflower plants in late summer or early fall, and allow the flowers to go to seed. Leave the faded flowers and seeds on the plant to add interest to your winter garden; birds and other animals will appreciate the snack. Remove the dead plant material in early spring before new growth begins. Flowers left on the plants over winter drop seeds on the ground, so you might prefer to remove the flowers and seed cones if you don't want more coneflower plants.

Mow the plants down to the ground in early spring once every few years if the coneflower patch becomes overgrown and messy. Additionally, coneflowers benefit from division once every two to three years in early spring. Dig up the plants, and divide the root balls into two or more sections. Replant one division in the original hole; discard the remaining divisions or plant them in new holes spaced 2 feet apart.