Gardeners and commercial growers alike are enjoying the mild winter so far, not worrying about those tender perennials or those later than should have been transplants out in the home landscape or overwintering production crops.
What may be a bit of concern is with the mild winter, so far anyway, is what are the insect populations looking like for 2016 and how are plants going to respond next spring if the dormancy triggers are not fully met.
Insects that survive the winter above ground do so because they can tolerate temperatures well below zero, so those insect populations may not be any different. Insects can also spend the winter in an egg stage or as a pupae. Pupae can be both above and in the soil or leaf litter.
Insects that are not winter hardy in our typical winter temperatures are currently surviving. If the mild winter weather pattern continues, these insects will already be here rather than traveling up from the south or other warmer parts of the country. An easy example of how weather impacts overwintering is the Japanese beetle. The beetle needs adequate soil moisture or perhaps a better way to say it is the grass plant they feed on needs adequate soil moisture to produce the roots they eat in late summer. We have not lacked for water this summer and fall. Another survival point is the Japanese beetle does not travel down in the soil profile as far as our native grubs, so a mild winter will allow them to survive in the soil as they won't get cause in the frost line.
About the only drawback that is possible is that the weather may actually remain too wet, allowing fungi to attack the insects in their resting stage.
Plants normally go dormant based on day length and come out of dormancy based on temperatures. Dormancy is the way our deciduous plants cope with the below freezing temperatures to survive the winter and triggers next years' blooms. The crystal ball is a bit cloudy right now, yet gardeners might expect to see some erratic blooming next year, both in terms of uneven blooming or perhaps later or earlier than what we typically expect. Landscape and nursery stock that have a tendency to come out of dormancy early and be damaged by late cold spring weather will be a concern too.
About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.