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The Garden Plot for February 20, 2009
3:55 PM - 4:00 PM
[Program Website]
Today's Highlight: “Pruning”
Days are getting longer, the end of winter is in site. Now is the time to get out and start pruning shade trees, fruit trees, and shrubs. Pick a sunny, dry day – it’s best for the plants and the pruner! Pruning now, just before spring growth starts, is generally the best timing for most plant species. It leaves fresh wounds exposed for only a short length of time before new growth begins the wound sealing process. Now it’s also easier to make pruning decisions. There are no leaves hiding the branch structure. Most importantly, pruning now can avoid certain disease and physiological problems.
Prune honey locusts now when they are still dormant to avoid stem cankers. If they must be pruned after the dormant period, avoid rainy or humid weather conditions.
Prune apple trees, flowering crabapples, mountain ash, hawthorns and shrub cotoneasters now to decrease the chances for infection and spread of the bacterial disease fireblight.
Now is a good time to shorten tall raspberry canes, or thin out crowded plants. You can remove the canes that fruited last summer on June-bearing raspberry cultivars. These canes are dead. Cut them as close to the ground as possible. If you have Everbearing raspberry cultivars (that produce fruit in the fall), remove only the top part of the canes; the part that fruited last fall.
Evergreen shrubs and trees should be pruned after the coldest winter weather is past, but before warmer temperatures (above 50 F) send plants their “wake-up” call. Now is a good time to tip back new shoots on Mugho pines so they won’t get leggy. It’s also a good time to thin out branches on thick Colorado Spruce. Dense spruce are more vulnerable to wind damage. You can also shape junipers, arborvitae, and cedars by tipping back the tops and sides of theses shrubs.
Many flowering shrubs can be pruned now or, after buds have begun to swell, but before buds turn green. Caragana and honeysuckle can be pruned now. Shrubs grown primarily for their foliage rather than showy flowers can also be pruned now, before growth begins. These species include dogwood, buffaloberry, ninebark, and sumac.
Plants with marginally hardy stems (such as clematis and shrub roses) can be pruned back to live wood now. Hardier shrubs such as late blooming spireas can be pruned to the first pair of buds above the ground.
There are plants that should not be pruned now. Some trees have sap that “bleeds” after late winter or early spring pruning. This bleeding causes little harm, but to prevent bleeding, prune the following trees after their leaves are fully expanded in late spring. Be careful never to remove more than 25% of the live foliage. Examples of tree species that are bleeders include: all maples, including boxelder, butternut, walnut, and birch.
Trees and shrubs that bloom early in the spring on last year’s growth should be pruned as soon as they finish blooming in the spring. Early-blooming tree species include apricot, flowering plum, chokecherry, and cherry. If you prune spring-flowering shrubs now, you may sacrifice all or most of this spring’s bloom. Spring-flowing shrubs include forsythia, lilac, and spring-blooming varieties of spirea.
For more information on pruning contact your local county extension agent.
Helen Atthowe's new short program of gardening tips
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