Indiana Department of Natural Resources sent this bulletin at 04/12/2023 07:35 AM EDT
Weekly Review for April 12, 2023
This informal report by the Division of Entomology & Plant Pathology is a commentary on insects, diseases, and curiosities division staff encounter on a week-to-week basis. Comments and questions about this report are welcome and can be sent to your respective Inspector.
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
There has not been much pest activity in my region yet; however, I am just starting to get out to garden centers this week to see what is being shipped into the state. The real issue I am seeing is winter injury in the landscapes. Many blue atlas cedars in my region are completely brown.
The Hortsman’s dwarf blue atlas cedar in my yard looks the same. There is severe needle browning, but the buds look good, and the wood is still green. All things considered, they are likely to grow out of this damage. I saw a similar situation during the winter of 1994 in Pennsylvania—even large specimens that had been there for years looked bad, but they survived. To help yours along, give plants like these a good fertilizing so they can flush a decent amount of new growth and establish decent foliage. I have also observed defoliation on blue hollies in Bloomington landscapes this year, but the buds look good.
Japanese cherries are not blooming much this year. My Yoshino cherry has only a few flowers. In previous years there have been so many flowers that you can hardly see the branches. I frequently see reduced flowering on this plant when temperatures reach -15F during winter.
Usually Prunus subhirtella ‘Pendula’ continues to flower in years when my Yoshino cherry has reduced flowering; however, I am even seeing reduced flowering on my weeping cherry this year. While visiting an arboretum in Bowling Green, Kentucky a few weeks ago, I observed severe winter injury on well-established Cryptomeria, Leyland cypress, and plum yews (Cephalotaxus). In many cases the winter injury was worse in that part of Kentucky than in southern Indiana.
Some plants that just did not seem to be affected by the severe cold snap that occurred on Dec. 23, 2022, which is the date I think caused most of the winter injury. Plants that seem to be flowering well are redbuds, flower dogwoods, and serviceberries. Interestingly, the hardier varieties of southern magnolia made it through this winter relatively unharmed in the Bloomington area. I also did not see any damage to green giant arborvitae. Unfortunately, there is still time for spring freeze. My Japanese maples are leafing out, and I hope temperatures do not drop below 28F again.
Over the weekend I was collecting the bees’ version of Easter eggs, pollen balls. I hope to get a half dozen samples of pure pollen to send to Mississippi State for nutrition analysis this year. USDA is funding a research project there and at Oregon State to catalog about 150 varieties of pollen from across the country. The study involves collecting straight pollen from flowers or collecting bees and robbing them of the pollen load they are carrying. To date I’ve collected some willow pollen and dandelion pollen. Doing so served as test runs for the bee/pollen vacuum I built. I am keeping my fingers crossed I will be able to get more samples this summer and fall.
