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Down the Garden Path

Dealing with Fruit Trees in this Weather

Our timetable to get dormant oils on and pruning done has been thrown out the proverbial window this year so far. The weather pattern has not given us even a couple days where it is safe to get on the dormant oil sprays. We will need, depending on the product used, at least one 24-hour period where temperatures remain above freezing. More commonly, we want 2 to 3 days of moderate temperatures to allow the dormant oils to work against overwintering insect adults, any eggs, and especially overwintering female scales. Other than the scale insects, which are right there on the surface of our branches, enough spray will need to be applied to get into cracks and crevices on the trunk and larger branches to suffocate insect adults and any overwintering eggs.

Dormant pruning will be different between young fruit trees where you are building strong scaffold branches that will hold the fruits without needing support and training systems and established home orchard fruit trees. In general, the traditional full-size apple tree will require the most pruning and if you are lucky enough to have a sweet cherry in the yard, the least pruning. Overall, the amount of pruning depends on species and if there are dwarf versions available. Starting with a full-size apple, the rest fall in line, peaches and nectarines, then come apricots, Japanese and European plums, then on to sour cherries, then spur-type apples and finally back to sweet cherries. It is easy to see why spur-type apples are the way to go in small backyards.

While we continue to have well below normal temperatures, there still is the opportunity to do some dormant pruning, but do it soon. The one fruit tree we wait to prune until it is blooming is the peach. Peach flower buds are very sensitive to severe winter cold weather to start with so we wait until they are blooming to do any pruning to prevent pruning off any flower buds before they actually open.

At some point, we will have more normal and consistent temperatures and once the spray season arrives, your timetable will return. Early sprays will be for cool, wet weather diseases and once past bloom, the cover spray schedule takes over. More frequent at first and then toward apple maturity, taper off to the days to harvest limitation listed on the label.

The more common sprays available will come in a liquid, making mixing much simpler. Because they are liquid, equipment also is more basic. Always read and follow label instructions. Either as the fruit trees grow in size or your number of trees increases, consider using wettable powder forms that will take a higher level of spray equipment. You get to mix only the pesticides you need and in general, wettable powders are less expensive. With any product, always read and follow label instructions.

Richard Hentschel is a Horticulture Extension Educator with University of Illinois Extension, serving DuPage, Kane and Kendall counties. Stay tuned to more garden and yard updates with This Week in the Garden videos at and the Green Side Up podcast at The Kendall County Master Gardener Help Desk is open for 2018. Current hours are Monday through Friday from 9 a.m. to 12:30 p.m. at 630-553-5823.