News
02-02-2007, 10:15 PM
With Pruning, Timing Is Everything
By Joel M. Lerner
Saturday, February 3, 2007
It's a good time to prune many dormant trees and shrubs. However, knowing exactly how, what and when to prune can be bewildering.
For instance, some plants shouldn't be cut now because flower buds that formed last year are going to bloom this year. So, what procedures should you follow?
Old-Growth Bloomers
Some deciduous shrubs that flower on previous year's growth are: deutzia, mock orange, forsythia, flowering quince, weigela, lilac and winter-flowering jasmine. Pruning requirements vary.
Deutzia flowers white in spring. Slender deutzia ( D. gracilis) requires selective pruning. It matures at four feet. Some hybrids grow lower. Nikko is a hybrid that is a good shrub as a ground cover in sun or partial shade with light maroon fall color. Prune all deutzias after flowering. Showy deutzia ( D. x magnifica) is a large, coarse-textured member of this genus and needs selective pruning to keep it full. It reaches 10 feet or more in maturity.
Mock orange ( Philadelphus coronarius) works into the shrub border well, with fragrant flowers in spring. It grows about 10 to 12 feet tall and wide in sun. Its showy bark stands out in winter. Do not cut in winter, even though it may look as if it needs it. Prune right after flowering by cutting out the oldest wood about a foot from the ground. Retain other canes for several years for the beautiful reddish exfoliating bark in winter. New growth from wood that's a couple of years old promotes flowering.
Forsythias are so vigorous in full sun that the best practice is to cut them to 12 inches high and wide every year after flowering. They lose ornamental value when sheared too often. If they are planted as a hedge, leave three feet of woody stems to keep the effect. The new long, graceful stems will flower along their entire length because they won't be pruned until after they flower.
Flowering quince ( Chaenomeles speciosa) can be fooled into early flower, as it was by the springlike weather we had this January. Reserve judgment and wait until its characteristic March blooming time before cutting. Renewal prune right after flowering, every five to six years, when stems reach five to six feet and are a tangled mass. Wear leather work gloves because of short barbs on old wood.
Weigela is a versatile shrub in many sizes, foliage hues and flower colors. It prefers full sun. Mature size is from three to nine feet high and wide, depending on the hybrid. Renew annually after flowering, correctively cutting dead and rubbing branches. Overgrown shrubs might require hard, selective pruning after flowering.
Lilac flowers should be cut off as soon as they fade. They can also be cut as they open and brought indoors for fragrance. The Washington climate is on the cusp of being too warm for profuse flowering, so site conditions should be carefully chosen. Lilacs prefer excellent air circulation; light, loamy soil conditions and a pH of 7. Pruning the big old wood to the ground will keep borers, their worst insect problem, from invading the wood. Cut down trunks that have become thick (two inches or more) and are starting to show furrows right after flowering. Cut oldest lilac wood annually and the plant will stay borer-free. Lilacs renew by shoots that grow from the roots. Flower buds form on them this year and open next.
Winter-flowering jasmine has yellow flowers that open intermittently, starting in January and continuing into early spring. Square stems stay green all winter. Their cascading habit makes them perfect for sunny slopes and walls. Cut to the ground in spring to renew every five to seven years.
Get Out Those Shears
Deciduous shrubs that benefit from hard pruning between now and late winter are those that flower and berry on the same year's growth. Cut any time before spring growth begins and to desired height.
Annabelle hydrangea ( H. arborescens), smokebush ( Cotinus coggygria) and chastetree ( Vitex agnus-castus) can be cut leaving some shrub mass, or you can take them down to the ground, leaving 6-to-10-inch woody stubs sticking out.
Prune bluebeard ( Caryopteris x clandonensis), purple beautyberry ( Callicarpa dichotoma), and St. John's wort ( Hypericum species) to short stubs in winter.
For a landscape with shrubs with a natural growth habit, cut broken branches and dead wood and perform light, corrective, selective pruning. Allow plants to grow to mature size. Some of these shrubs are: itea, spicebush ( Lindera benzoin), summersweet ( Clethra alnifolia), arrowwood viburnum, false cypress ( Chamaecyparis species) and American euonymus.
Cut back to a foot or less red- and yellow-twig dogwoods ( Cornus sericea) to give their best performance the same year. Leave their showy red or yellow stems until the end of the winter, then cut these fast-growing, shrubby dogwoods to 12 inches before spring growth begins. The best color is on the younger stems.
Prune winterberry holly ( Ilex verticillata) if it looks unkempt or leggy after the berries lose ornamental value in winter. The flushes of berries atop this holly are the perfect complement to the red and yellow twig dogwoods. They tolerate wet feet well and don't need pruning in a natural setting.
Crape myrtles flower summer into fall. Many have beautiful fall foliage and handsome exfoliating bark. The trunks have a showy appearance in winter. Do not prune these woody, late-leafing large shrubs or small trees until growth begins in spring. Do this by cutting out stems and simplifying their trunks into a grouping of three to five. Too many trunks reduce the bark's ornamental value.
This is also the time to consider your shade trees. Prune deciduous trees. Don't top them. Retain the central trunk and tops of main branches. Give them a thorough clean-out and assessment. Do this every three to five years or as needed. Use a tree company for larger specimens. Prune crossing branches where bark rubs, limbs growing toward the inside of the tree, dead wood, and lower limbs up to six to eight feet above ground level.
Cut branches at branching limbs or to the trunk. Don't leave half branches or short stubs sticking out. Leave the one-quarter to three-quarter-inch flare that appears at the base of a branch. The slightly wider flare, called the branch collar, is where scar tissue forms that heals the cut.
Cut all suckers, also called water sprouts, that grow from the roots, branches or trunks of trees. These stems extend straight up and grow quickly, three to four feet, without branching. They rob the main trunk and canopy of nutrients and light.
Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site,http://www.gardenlerner.com.
By Joel M. Lerner
Saturday, February 3, 2007
It's a good time to prune many dormant trees and shrubs. However, knowing exactly how, what and when to prune can be bewildering.
For instance, some plants shouldn't be cut now because flower buds that formed last year are going to bloom this year. So, what procedures should you follow?
Old-Growth Bloomers
Some deciduous shrubs that flower on previous year's growth are: deutzia, mock orange, forsythia, flowering quince, weigela, lilac and winter-flowering jasmine. Pruning requirements vary.
Deutzia flowers white in spring. Slender deutzia ( D. gracilis) requires selective pruning. It matures at four feet. Some hybrids grow lower. Nikko is a hybrid that is a good shrub as a ground cover in sun or partial shade with light maroon fall color. Prune all deutzias after flowering. Showy deutzia ( D. x magnifica) is a large, coarse-textured member of this genus and needs selective pruning to keep it full. It reaches 10 feet or more in maturity.
Mock orange ( Philadelphus coronarius) works into the shrub border well, with fragrant flowers in spring. It grows about 10 to 12 feet tall and wide in sun. Its showy bark stands out in winter. Do not cut in winter, even though it may look as if it needs it. Prune right after flowering by cutting out the oldest wood about a foot from the ground. Retain other canes for several years for the beautiful reddish exfoliating bark in winter. New growth from wood that's a couple of years old promotes flowering.
Forsythias are so vigorous in full sun that the best practice is to cut them to 12 inches high and wide every year after flowering. They lose ornamental value when sheared too often. If they are planted as a hedge, leave three feet of woody stems to keep the effect. The new long, graceful stems will flower along their entire length because they won't be pruned until after they flower.
Flowering quince ( Chaenomeles speciosa) can be fooled into early flower, as it was by the springlike weather we had this January. Reserve judgment and wait until its characteristic March blooming time before cutting. Renewal prune right after flowering, every five to six years, when stems reach five to six feet and are a tangled mass. Wear leather work gloves because of short barbs on old wood.
Weigela is a versatile shrub in many sizes, foliage hues and flower colors. It prefers full sun. Mature size is from three to nine feet high and wide, depending on the hybrid. Renew annually after flowering, correctively cutting dead and rubbing branches. Overgrown shrubs might require hard, selective pruning after flowering.
Lilac flowers should be cut off as soon as they fade. They can also be cut as they open and brought indoors for fragrance. The Washington climate is on the cusp of being too warm for profuse flowering, so site conditions should be carefully chosen. Lilacs prefer excellent air circulation; light, loamy soil conditions and a pH of 7. Pruning the big old wood to the ground will keep borers, their worst insect problem, from invading the wood. Cut down trunks that have become thick (two inches or more) and are starting to show furrows right after flowering. Cut oldest lilac wood annually and the plant will stay borer-free. Lilacs renew by shoots that grow from the roots. Flower buds form on them this year and open next.
Winter-flowering jasmine has yellow flowers that open intermittently, starting in January and continuing into early spring. Square stems stay green all winter. Their cascading habit makes them perfect for sunny slopes and walls. Cut to the ground in spring to renew every five to seven years.
Get Out Those Shears
Deciduous shrubs that benefit from hard pruning between now and late winter are those that flower and berry on the same year's growth. Cut any time before spring growth begins and to desired height.
Annabelle hydrangea ( H. arborescens), smokebush ( Cotinus coggygria) and chastetree ( Vitex agnus-castus) can be cut leaving some shrub mass, or you can take them down to the ground, leaving 6-to-10-inch woody stubs sticking out.
Prune bluebeard ( Caryopteris x clandonensis), purple beautyberry ( Callicarpa dichotoma), and St. John's wort ( Hypericum species) to short stubs in winter.
For a landscape with shrubs with a natural growth habit, cut broken branches and dead wood and perform light, corrective, selective pruning. Allow plants to grow to mature size. Some of these shrubs are: itea, spicebush ( Lindera benzoin), summersweet ( Clethra alnifolia), arrowwood viburnum, false cypress ( Chamaecyparis species) and American euonymus.
Cut back to a foot or less red- and yellow-twig dogwoods ( Cornus sericea) to give their best performance the same year. Leave their showy red or yellow stems until the end of the winter, then cut these fast-growing, shrubby dogwoods to 12 inches before spring growth begins. The best color is on the younger stems.
Prune winterberry holly ( Ilex verticillata) if it looks unkempt or leggy after the berries lose ornamental value in winter. The flushes of berries atop this holly are the perfect complement to the red and yellow twig dogwoods. They tolerate wet feet well and don't need pruning in a natural setting.
Crape myrtles flower summer into fall. Many have beautiful fall foliage and handsome exfoliating bark. The trunks have a showy appearance in winter. Do not prune these woody, late-leafing large shrubs or small trees until growth begins in spring. Do this by cutting out stems and simplifying their trunks into a grouping of three to five. Too many trunks reduce the bark's ornamental value.
This is also the time to consider your shade trees. Prune deciduous trees. Don't top them. Retain the central trunk and tops of main branches. Give them a thorough clean-out and assessment. Do this every three to five years or as needed. Use a tree company for larger specimens. Prune crossing branches where bark rubs, limbs growing toward the inside of the tree, dead wood, and lower limbs up to six to eight feet above ground level.
Cut branches at branching limbs or to the trunk. Don't leave half branches or short stubs sticking out. Leave the one-quarter to three-quarter-inch flare that appears at the base of a branch. The slightly wider flare, called the branch collar, is where scar tissue forms that heals the cut.
Cut all suckers, also called water sprouts, that grow from the roots, branches or trunks of trees. These stems extend straight up and grow quickly, three to four feet, without branching. They rob the main trunk and canopy of nutrients and light.
Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site,http://www.gardenlerner.com.