Get out your shears. It’s time to prune.
Deciduous shrubs like lilac and forsythia that flower in the spring will need pruning depending on their condition and growth. If they have been neglected for a while these spring-flowering shrubs may need extensive cutting back sometime between mid-February and early-April, before the plants begin to leaf.
While heavy pruning in late winter or the early spring will reduce or stop the flower display for a few years, the health of the shrub is more important. If your flowering shrubs need only light pruning, prune them immediately after blooming. Pruning straight after blooming allows you to enjoy the blossoms but gives the shrubs time to start their flower buds for next year.
Summer-flowering shrubs can be pruned now, in early spring (from mid-February to early April) and will still bloom in summer. Prune summer and fall blooming shrubs like Spirea, Potentilla, Weigelia, Hydrangeas, now. Late winter pruning will not interfere with summer flowering and allows the plants to recover quickly.
Many deciduous shrubs don’t produce attractive flowers. These shrubs may possess attractive bark, fruit, or fall leaf color. Prune these shrubs in late winter or early spring.
Prune evergreen shrubs, such as juniper and yew, in late March or early April before new growth begins. Note: Don’t prune evergreen shrubs in the fall as they become susceptible to winter injury.
The best time to prune deciduous trees is late winter or early spring (February, March, and early April) before they begin to leaf out. Some trees, such as maples, “bleed” heavily when pruned in late winter or early spring. However, the heavy bleeding doesn’t harm the trees. The trees won’t bleed to death and the flow of sap will gradually slow and stop.
To prevent the spread of oak wilt, avoid pruning oaks from April 1 to July 1. Pruning oaks during this period may attract sap beetles carrying the oak wilt fungus to the pruning cuts and transmit the disease to healthy trees. An excellent time to prune oaks is February and March.
If possible, avoid pruning deciduous trees in the spring as they are leafing out. At this time, the tree’s energy reserves are low and the bark “slips” or tears easily. Another poor time to prune is during leaf drop in the fall.
An excellent time to prune spruce and fir is late winter when they are still dormant. Spruce and fir possess side or lateral buds. The pruning cut should be just above a side bud or branch. Prune pines in early June to early July when the new growth is in the “candle” stage. Pinching or snapping off one-half to two-thirds of the candle reduces the pine’s annual growth. Unwanted lower branches on all evergreen trees can be removed in late winter.
The best time to prune fruit trees is late February to early April. Remove dead wood, branches that cross and any suckers that have started. Saw or cut close to a bud, branch joint or trunk. Don’t leave a nub as it will attract and house bugs. Let in light as the fruit will form easier. Keep horizontal branches and prune vertical branches. After you are done pruning you can apply dormant oil* if you experienced problems with mites and scale last year.
Prune grapevines in March or early April. Grapevines pruned at this time of year will bleed heavily. However, the bleeding will not harm the vines.
Cut down ornamental grasses to 6-10 inches above the soil line. Don;t plant winter seed as it’s too late and don;t plant spring seed as it’s too early.
Prune the upper portions of modern roses, such as hybrid teas, floribundas, and grandifloras. Typically these die because of winter temperatures. Prune out the dead wood from modern roses in late March to mid-April.
Old garden roses, hybrid rugosas, and other hardy roses often survive cold winters with little or no winter injury. Those that bloom only once a year should be pruned immediately after flowering. Those that bloom throughout the summer should be pruned in March or early April.
Horticultural Oils or Narrow Range Oils are lightweight oils, either petroleum or vegetable based that are used in horticulture and agriculture, as a dilute spray on plant surfaces to control insects and mites. The oils provide control by smothering the target pests, and are only effective if applied directly to the pest, and provide no residual controls. Oils are generally considered suitable for ‘organic pest control’, with most oils permitted under the U.S. National Organic Program.
Thanks to Iowa State Outreach.