It may seem that every time a gardener turns around, there is some other disease to worry about. Gardeners, pay attention, because there is another new one but it is NOT in Minnesota at this time. Resident gardeners will need to pay attention to any rhododendrons that you may have purchased this year, according to the Minnesota Department of Agriculture.

We generally deal with new problems in the garden via insects but this time it is a pathogen that causes Sudden Oak Death Disease. According to the U of M and the MDA, “the rhododendron plant is a carrier of this invasive plant pathogen called Phytophthora ramorum. The spores spread to oak trees and cause sudden death.”

We need to keep any eye on our rhododendrons and see if they are displaying any diseases. According to the MDA, “Infected leaves of rhododendrons have large, brown blotches. Young green stems and shoots turn brown and shrivel. Leaves attached to the infected stems wilt and may have a dark brown line extending down the center of the leaf from the base. Just FYI — this invasive pathogen often does not kill rhododendrons.” Seems a bit tricky but it is certainly worth keeping an eye open for any problems. This disease is currently in California and Oregon.

It seems that planting oaks and ash trees are going to be a thing of the past. We are still dealing with Dutch Elm disease too. We need to make sure that we are not planting all the same kind of tree in our growing spaces so that if there is a disease or insect that comes along, it won’t wipe out our whole tree population in each person’s individual yards or groves.

If you are into raising trees or looking for information on trees that seem to have the least amount of insect and/or disease problems, head over to MyMinnesotaWoods.com There are many other trees to choose from that are beautiful and work well in our landscape. This is a website that is connected to the U of M and is used not only for people who are looking for the right tree for their backyard but also for people who are looking to go into the agroforestry production too.

Master Gardeners are often those who hear about new plant diseases and insect problems before most other residents do. Healthy plants, healthy people, and a healthy planet are the top University of Minnesota Extension Master Gardener priorities: Horticulture skills. Master Gardener volunteers engage people with hands-on learning and act as trusted resources for community members. Join us! Find out how to apply to become a Master Gardener volunteer: mgweb@umn.edu or call (507) 828-5754 for more information. If you have any questions regarding your garden you can also email me at s.dejaeghere@me.com