By Dawn Pettinelli, UConn Home & Garden Education Center
About now the gardens should be planted, and it is time to turn our attention to the trees and shrubs on the property. New growth is almost fully expanded and pruning of spring flowering shrubs can commence. When out there with your pruners, keep an eye peeled for suckers and water sprouts, both on the plants you’re pruning and other woody plants in the yard.
Many trees and shrubs produce vigorous, upright stems that can reach several feet high over the growing season if left unchecked. Those arising from the root system are known as suckers while those growths arising from the crown portion of a tree or large shrub are referred to as water sprouts. At the very least, they are unattractive and take away from the architectural framework of a plant. More importantly they use water, nutrients and energy that could be put to better use if not taken from the rest of the plant. If not removed, they can crowd out the main plant resulting in reduced vigor.
Some woody plants naturally tend to produce suckers and sometimes these young vigorous shoots are needed to rejuvenate older plants as aging stems are removed. An example would be shrubs like red-twigged dogwoods or lilacs. Suckers arising from trees such as apples, crabapples, honey locust, lindens and others, however, should be removed.
In the case of grafted plants, like hybrid tea roses or apples, the desired variety is grafted on to a rootstock that might be more cold hardy, have dwarfing genes or other desired features. Occasionally the rootstock revolts, so to speak, and sends up its own shoots. In the case of roses, one might notice a stem with red flowers when the plant was purchased as a named cultivar with different colored flowers.
Suckers and water sprouts often occur because plants are in some way stressed or due to damage to their root system. Plants can be under stress for a number of reasons. Some common reasons would be insect or disease problems, drought, too high of a water table, compacted soil and/or difficult growing conditions.
Planting too deep will also stress a plant and could cause suckers to develop. Whenever planting woody plants sink them so that the level of soil in the pot they are grown in is level with the soil they are planted in.
Another reason for suckers or water sprouts is that plants are pruned incorrectly or too drastically. Seldom is it advisable to remove more than one-third of the plant at one time. Also, avoid topping ornamental or woodland trees.
Ideally suckers and water sprouts should be removed as soon as they are produced. Often, they can just be rubbed or twisted off in spring as their stem is just starting to expand. Once they reach pencil-size in thickness, cut with clean, sharp pruners. Do your best to remove them flush to a limb or as close to the tree’s trunk or root system as you can. Don’t leave stubs as these will likely have buds at their base and just regrow.
Speaking of suckers, there are often questions when growing tomatoes about what to do with the sprouts popping up where the leaf attaches to the main stem. Typically suckers just form on indeterminate tomato varieties, which are those that continue to grow, bloom and set fruit as long as growing conditions allow. If all suckers are left on the plant, it becomes quite unruly and hard to stake. Also, fruit will be plentiful but usually smaller.
Usually, the suckers below the first fruiting cluster are removed so the development of those tomatoes won’t be slowed. Then it is up to individual gardeners to decide whether to leave suckers or not and how many to leave. Often a few are left to increase and extend the harvest. Tomatoes in our area are prone to many leaf diseases, especially during humid and wet seasons. As the bottom leaves yellow and die, it is beneficial to let some of the suckers on top grow so plants can produce more foliage to yield food for the plant and to shade the developing fruit. Some experimentation might be necessary keeping in mind that it is better to remove too little than too much.
For questions about pruning suckers and water sprouts or on other gardening topics, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension Center.
