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Over the Garden Fence

Unseasonable weather makes for early plant arrivals

white flowers with blue lines

Over the past several weeks, residents in northern Illinois have experienced some unseasonable weather. Warm, spring-like temperatures, thunderstorms, rain, hail, sleet, and snow have been the reality along with 70-degree high days with 20-degree low nights. All of these warm days have woken our plants and brought them out of dormancy a month or two early, depending on the species.

Even though it has felt like spring, spring frosts are still expected in northern Illinois. It can be hard to resist putting out new plants and getting a jump on Spring planting. There have been many questions coming into the Extension Offices about the effect of the “false Spring.”

To prune or not to prune

The first question has been foremost for those who were still working on early spring dormant pruning, “Should we do that pruning now that there are leaves out?” The short answer is no and wait to do your pruning later at the end of the season for a backyard gardener. Spring growth relies on environmental cues like the warm temperatures to bud out. Dormant pruning is an invigorating experience for the plant similar to giving the tree fertilizer. Both actions aid in growth and development.

Since we are past bud break stage for trees, flower buds are in the process of growing. On spring flowering plants and fruit trees, pruning now can cost you those flowers and fruits this season. For flowers that have this year’s buds beginning to grow like magnolias, it is best to prune them after flowering. For fruit trees, it is best to prune them after harvest during those dormant months.

What does this mean for your fruit trees if left unpruned? Fruit plants require chilling hours to produce fruit the next year. These chilling hours are time spent between 32 degrees and 45 degrees. In northern Illinois, we have had no problem getting our chilling hours to produce fruit. This past winter is no exception. With the chilling hours present, fruit plants will produce flowers and fruits. With unpruned plants, you may see a reduced load of fruit this season. One thing you can do after the risk of frost is “maintenance prune” your fruit trees. This involves removing any dead, diseased, water sprouts, or crossing branches. Removing water sprouts and crossing branches opens your tree’s canopy, allowing for more light interception into the center and increasing air flow to reduce opportunities for disease.

Spring flowers have sprung

Another common question that has been coming into the Extension offices is “My flowers are up since end of February and we are having cold nights, will they be okay?” Yes, they will be okay. You may see some cold injury on the leaves but the crown under the soil should stay warm as the ground has been warming.  Hyacinths, daffodils, and tulips are all flowering in various stages of support. Depending on the weather your area received last week, you may see floppy plants from hail damage or snow coverage. These plants will stiffen up as sunny weather and breezy days help to rigidify the plants. Cold damage and hail damage may be seen in multiple ways or stages. Yellowing of the leaf tips back is the light stage of cold damage. Browning or blackening of the leaves can be seen in extreme cases where the plant leaves could not survive the cold damage. These leaves can be removed with pruners from the plant.

For any future frosts or freezes, use blankets, towels, or bedsheets to cover plants to insulate them from the cold temperatures. These can be removed if the temperature warms up between cold temperature days or nights. Secure them with heavy objects like bricks or bags to soil to prevent them from blowing away during breezy days.

For any questions about what is happening in your yard or your plants, contact your local Extension office to speak with the Illinois Master Gardener Help Desk or Extension staff for research-based solutions to your questions.


About the author: Bruce J. Black is the University of Illinois Extension Horticulture Educator serving Carroll, Lee, and Whiteside, & Boone, DeKalb, and Ogle counties. Black’s primary areas of expertise are in fruit and vegetable production, plant propagation, and community and youth garden education.