Timely Tips from Over the Garden Fence

You can catch George Wedel on Over the Garden Fence, 9:05 am Saturdays on AM 590 WKZO. And return here each week at www.wedels.com for the latest in Wedel's timely tips.

TIMELY GARDEN TIPS FROM OVER THE GARDEN FENCE AUGUST 16, 2003 To prune or not to prune, when is the proper time to prune, how much to prune off, these are questions Wedel's Michigan Certified Nursery Specialists are asked very often. I thought this morning "Over the Garden Fence" we would share some pruning basics. There are several good reasons for pruning plants that have value to you. 1.) To remove broken, weak, dead, and pest-injured branches. 2.) To remove crossed branches, water sprouts, poor angles, double leaders, and to direct growth. 3.) To encourage flowering and fruiting. 4.) To enhance the natural beauty of plants. 5.) To thin out older shoots to keep shrubs vigorous. Now about when to prune: A.) Trees and shrubs that bloom in the spring on previous year's growth, sometimes called "old wood", should be pruned after flowering. Examples would be forsythia, lilac, cherry, honeysuckle, spring blooming spirea, and dogwood. Pruning spring flowering trees and shrubs directly after flowering will allow the plant to develop bloom buds for next year's flowers. The exception to this rule is the plants in the rosaceous family which include crabapple, cotoneaster, pear, quince, and mountain ash. These plants are all susceptible to fire blight. Fire blight is a bacterial disease that can quickly kill these plants. Fire blight will enter a rosaceous plant through pruning wounds. To minimize the chance of infecting crabapple, mountain ash, quince, cotoneaster, and pear, prune these plants when they are dormant in early March. B.) Summer flowering trees and shrubs that flower on the current year's growth should be pruned in late winter or early spring. Examples would be summer blooming spirea, Althea Rose of Sharon, Caryopteris, butterfly bush, Potentilla, and Hypericum. Pruning these plants before new growth begins in March or early April will keep plants compact and promote summer blooms. C.) Broadleaf evergreens such as rhododendrons, hollies, azaleas, mountain laurel, and Pieris Japonica should be pruned just after new growth is complete, usually in early June. D.) Home orchard trees such as apple, pear, and cherry should be pruned the first week in March. Nectarine, peach, and apricot trees are pruned first week in April. E.) Needled evergreens including pine, spruce, and fir are pruned after new growth is complete, June 15th to 30th. Arborvitae, juniper, and yews are best sheared in April or July. Hemlock appreciate late July to mid-August pruning. F.) Hydrangea shrubs are best protected from winter damage like a rose bush. In the spring, only prune off dead branches. G.) Shrubs planted for their foliage, not their blooms, such as privet and euonymus burning bush can be pruned April through mid-July. H.) Shade trees are less critical as to pruning time. The easiest time to prune trees is when they are dormant, November through March. Viewing the entire tree's branch system is best when there are no leaves to block the view, also there is less clean up when there are no leaves. It is very important to prune oaks when dormant to avoid the spread of oak wilt. I.) I recommend using tree wound paint over all sizeable branch cuts. Pruning paint will help keep out damaging bacterial diseases. Necessity often dictates pruning time, but avoid major pruning projects after mid-August. Pruning stimulates plant growth: too much growth in the autumn sets up the plant for winter damage. An additional point to remember is to always use sharp pruning tools. If you don't now own sharp pruning tools, buy good quality forged steel ones that can be sharpened and will last for years. If you are inexperienced, get an Ortho pruning book. The illustrations and instructions are very helpful. I always fertilize plants right after pruning with the appropriate Plant Tone product to stimulate the new growth that will give your plant that finished look. My last suggestion on pruning: if the need has been determined, don't let someone talk you out of it. Ninety-nine percent of the time, pruning will enhance the looks of your plants and extend their life of usefulness. Fall webworm tents are now appearing in crabapple, cherry, and walnut trees. These unsightly worms can be easily destroyed with one spray of Take-Down Pyrethrin or Sevin. Rust has become a pesky problem in many lawns because of the cooler than normal temperatures in July and early August. Rust disease creates yellow and brown spores on turf leaf blades. Control lawn rust with sprays of Fertilome Systemic Fungicide. Red Thread is also rampant on many lawns. Rye and fescue grasses are most prone to Red Thread problems. A spray of Systemic Fungicide will usually clear up Red Thread. To help lawns resist Red Thread and rust diseases, step up your fertilizing program. An application of Scotts Super Turf Builder or Turf Nurture will reward you with a great response of green. Walking through the flower garden this morning reveals many exciting projects. Number one on our list is to assess the amount of August color there is in our flowerbeds. Anemonies, phlox, caryopteris, dianthus, nasturtiums, geraniums, marigolds, and petunias are blooming now with sedums, dahlias, asters, and mums getting ready to flower very soon. This still leaves a few dull spots where larkspur, early dahlias, peonies, astilbe, and oriental poppies bloomed earlier, creating openings for new perennial plants. The following plants are great perennials for August color. Yellow happy Returns daylilies, golden Stella d'Oro daylilies, Joe Pye weed with it's long lasting lavender blooms, double yellow flowering helianthus, and hibiscus in red, white, and pink flowers are some of my favorites. Is there a magnolia or tulip tree in your landscape? If so, be sure to examine it closely for scale infestation. Scale insects are very numerous on magnolia and tulip trees in many neighborhoods. Scale can cause the death of branches. Scale insects also leave sticky drips of honeydew on everything under the tree, which then attracts a ton of other insects to the infected area, like yellow jacket bees. Control scale with sprays of Safe-T-Side Horticultural Oil mixed with Malathion. Usually, scale-infested plants are covered with black mildew growing on the honeydew. One spray of Halt Fungicide will clean up the mildew. It is also time to begin thinking about spring garden color. This means it's time to give our German iris plantings some attention. Iris rhizomes should be dug up now and examined for borer damage. If borers are found, cut out the damaged area of the rhizome and treat the cut end with Consan disinfectant. This will help prevent disease infection in the rhizome. Separate the clumps so that individual toes with at least one good eye can be replanted. Plant bearded iris in a sunny area with well-drained soil for the best results. Mix bone meal into the soil before planting, using two tablespoons per rhizome. Plant rhizomes just under the soil surface. This is also a good time to add to your iris collection. Down at the garden center, we have just received our fall shipment of twenty named varieties for planting right now. Varieties such as Gold Galore, Breakers, Summer Olympics, Spartan, Rare Treat, Beverly Sills, So Fine, and many more are all as beautiful as any orchid could ever be. Plant bearded iris now, then just wait until spring for some of the most beautiful, carefree blooms in your perennial garden. George Wedel

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