In early spring, it's a good idea to assess your garden to see what Mother Nature has done during the winter months and to administer first aid for any damaged plants and shrubs. Master gardener Chris Dawson demonstrates how to correctly prune perennials. Essential pruning tools include hand shears, loppers and pruning shears.
There are many different types of perennials, but some general tips apply to cutting back and pruning all perennials. When trimming dead branches and leaves from perennials, clean out the debris and remove it from the garden because old leaves and dead branches may contain diseases that can infect the new shoots.
Small shrubs are very attractive to rabbits and deer, who like to munch on the branches of landscape shrubs. Wherever snow accumulates through the winter, damage from rodents can be severe. Rabbits walk on top of the snow and feed on the tips of high branches, and voles can burrow under the snow and girdle the bark off young trees.
To prune back any animal damage, use hand shears on outward-facing buds of bushes, such as azaleas, to encourage new outward growth. In early spring, prune shrubs only to correct any animal damage. Typically, azaleas and other spring flowering shrubs should be pruned after they bloom; if you prune beforehand, you'll lose some of the flowers for that season.
Here's how to prune specific perennials:
- Vines should be checked for winter damage and tied back to their trellises when needed. To prune and remove broken branches on clematis, prune it back to just above a live bud that is starting to sprout. Do any other pruning on clematis after it blooms.
- Wisteria are strong vines and need a sturdy support to grow on, like a freestanding arbor. Even if they aren't damaged from winter conditions, they do require annual maintenance. Early spring is the best time to prune wisteria to reduce rampant growth. After it blooms, it will need to be pruned back again.
- Ornamental grasses not only add color and texture to a garden in the summer but also add interest in the winter with their wispy, dry flower spikes and thin, golden leaves. By springtime, though, they can look worn down. Remove the old, dead foliage by shearing it fairly close to the ground before new leaves start emerging through the dead foliage. Prune early in the spring, because if you have a warmer area around your home, like the south side, the ground thaws and plants begin to grow earlier in the season. Be careful not to cut new leaves as you clean out the old ones.
- A lot of perennials such as hardy geraniums, Missouri primrose, and artemesia, look great in the garden late in the season, but before growth starts again in the spring, the old dead foliage needs to be cut back just above ground level to make room for new growth.
- Chrysanthemums also need to be trimmed back in early spring . If you live in the southern zones, where the soil doesn't freeze and thaw several times during the winter, you can cut the foliage back on mums after it dies in the fall. However, if you live where there is constant freezing and thawing in late winter or where you get a lot of snow cover, it's a good idea to leave the dead stems on the plant. These stems help hold the snow around the plant to insulate it. Mums lack hardiness in zones 4 and colder because the constant freezing and thawing heaves the plants out of the ground, exposing their roots to the air, drying them out.
- Roses require special care because of their thorns. Always wear thick, heavy gloves when working on roses to protect your hands. All roses need to be checked for winter damage, regardless of whether they're in a snowy area or not. Use hand shears to cut their canes back to the point where there is live wood and just above an outward facing bud. Also remove all weak, broken, and willowy stems. Nature's signal for the appropriate time to prune roses in your area is when forsythia is in bloom.
- Hibiscus emerges very late in the spring, so be patient. Cut it way back so that new shoots will bush out, and apply a soluble plant food once the hibiscus sprouts shoots.
Drastically cutting back a shrub is called "coppicing." But before you do this, make sure you know a shrub's growth habit. It works best with shrubs that flower on new wood rather than old wood and grow from spring buds, and with shrubs that are grown primarily for their beautiful foliage. Coppicing is done for several reasons:
It stimulates rapid growth of new shoots that produce larger, bolder foliage.
- The variegation in the leaves become more intense.
- The plants produce more flowers and fruits.
- It keeps the plant in bounds.
Coppicing is done in early spring, about a month before new growth emerges. Use loppers or a pruning saw, depending on the size of the stem, and cut the stems back to five inches above the ground.
This technique can be done to many different types of shrubs, including:
- Smoke bush or smoke tree (Cotinus coggygria), zones 4-8
- Abelia (Abelia x grandiflora), zones 5-9
- Butterfly bush (Buddleia davidi), zones 5-9
- Trumpet vine (Campsis radicans), Zones 4-9
- Blue mist shrub (Caryopteris x clondonensis), Zones 6-9
- Pee gee hydrangea (Hydrangea paniculata 'Grandiflora'), Zones 3-8
- Firethorn (Pyracantha coccinea), Zones 6-9
- Pussy willow (Salix spp.), Zones 4-8
- Tamarix (Tamarix ramosissima), Zones 2-8
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