September is not a good month to do a lot of pruning on shrubs and deciduous trees (trees that lose their leaves in the fall). Deciduous trees can be pruned after they have lost all their leaves and have gone dormant. But the best time to prune them and fruit trees is in late February or early March. Conifers can be pruned, if needed, after you are sure they have gone dormant, which will be after a couple hard freezes (temps in the low 20’s). Pruned in mid-December the branches of conifers are good for Christmas arrangements and wreaths.     

Butterfly bush (Buddlia davidii) may be pruned this fall after it goes dormant, or I like to wait and see what winter kills and prune next spring. Our STAR Magnolia (Magnoliaceae stellata) bush already has big flower buds, so we only prune it after blooming in the spring. Magnolia trees and shrubs need very little pruning.  The biggest problem with a Magnolia is protecting those flower buds over the cold winter and from a late frost. Dead wood can be and should be removed at any time.  

          Your hybrid tea, grandiflora, Old English (David Austin), and floribunda roses bloom on new wood so they can be pruned after a couple hard freezes (temperatures in the lower 20’s or colder). It is usually desirable at that time to just top roses at about 24”-30” so they do not blow in wind and break off. Then in the late spring after the Roses have started to wake up, prune out any canes or parts of canes that have winter killed or are longer than desired.

For winter we store my large tomato cages over the top and put wood chips around them for the winter. We do not do this until after the ground has frozen which is usually around Thanksgiving. Do not put mulch on too early or it will keep the soil warm and not let the Roses go dormant before a hard freeze. The purpose of the mulch on the roses and other perennials is not to keep the ground warm but to keep the ground cold and avoid the freezing and thawing. More trees, shrubs, and plants are winter killed by the freezing and thawing that takes place in the winter and early spring, than by the cold temperature. DO NOT prune most climbing roses as they bloom on old wood. Pruning now will remove flowers for next year.  Next spring prune only those canes that have winter killed or are longer than desired.  

          DO NOT prune most spring blooming shrubs in the fall, such as lilac, forsythia, bridal wreath spirea, and flowering almond. If you prune the shrubs now you will be cutting off the flowers for next year. Prune these spring blooming shrubs right after they bloom by taking out 1/4th to 1/3rd of the biggest, oldest canes all the way to the ground. This will reduce the height of the plant and open it up. This method also helps to control insect damage and especially lilac borers as they like the old, weak canes. By pruning you help get rid of the borers in the old wood.  Also by pruning you have a new bush every 3 to 4 years and more flowering throughout the bush as the flowers usually bloom on the tips of branches. Dead wood can be and should be removed at any time.

          DO NOT prune fruit trees, most deciduous trees, and most conifers (evergreen) trees and shrubs between the first week in August and the time they go dormant which is after Thanksgiving. Pruning encourages new growth and this new growth usually does not mature and winter kills. DO NOT APPLY ANY DRESSING SUCH AS TAR, PAINT, OR WOUND DRESSING TO THE CUT SURFACE. Research has found that trees do better when left to heal naturally.

Drying out from the cold winds when the ground is frozen is also a problem for conifer trees and shrubs that have already set their flower buds. Spraying an anti-desiccant or an anti-transpirant like “Wilt-Pruf” or “Wilt-Stop” really helps. Do this about Christmas time on a day when the temps are above 40 degrees F. and repeat about Valentine’s Day, and again about Easter.

Copyright 2015