As we start to decorate our homes and yard with greenery for the holidays, there are a few things to keep in the back of your mind as you are out purchasing wreaths, Christmas trees, and other plant material. There are quite a few of these plant materials coming into Minnesota from other states and they may include some hitchhikers. These hitchhikers are often pests and diseases that can infect our trees and shrubs in Minnesota.

According to the Minnesota Department of Agriculture, these diseases and pests are often the ones we don’t normally see here and we need to look for them before we purchase any items. You can check out the MN Department of Ag’s information on this topic at the following link: https://www.mda.state.mn.us/plants-insects/holiday-greenery-best-management-practices.

The most important thing to do is to remember where the proper place is to dispose of these items once the holidays are in past. According to the MN Department of Ag website, these pests can be carried into your yard through the purchase of these natural decorations. So it is important that once residents are done using them that we dispose of them in our local city tree disposal sites. Do not leave these materials sitting in your compost pile or sitting out in your grove. By doing this, you may allow the disease, insect, or plant material an opportunity to spread in our area.

Gypsy moth, elongated hemlock scale, spotted lanternfly, Brown marmorated stink bug, and Japanese maple scale are some of the invasive insects that we will need to look for. These insects are a problem because quite often they can live and reproduce on many different native and conifer trees in Minnesota. These insects and diseases quite often have a large impact on not only the trees in our yards but also in our groves and forests. Gypsy moth is in Minnesota in Lake and Cook counties. Elongate hemlock scale has been found in Minnesota but has not been found in the landscape and natural areas. Brown marmorated stink bug is established in Minnesota and the Japanese maple scale is not in Minnesota currently. Spotted Lanternfly is not currently in Minnesota. Even though some of these are not found here, we need to be vigilant to make sure to say something if we think we see it.

Some several diseases and weeds can cause some significant problems as well. Sudden Oak Death and boxwood blight have not been found in Minnesota but with resident’s help, we can keep it that way. 

There are a couple of plants that are often used as decorations in different greenery that is sold in Minnesota. If you see some of these, choose not to purchase those items. Oriental bittersweet is established in parts of Minnesota and is listed as “prohibited eradicate” on the Minnesota Noxious Weed List. As well as Oriental bittersweet, multiflora rose has also been located in Minnesota and is listed on the “restricted” on the Minnesota noxious weed list.

The one key disease to watch for is the elongated hemlock scale. This is because, in the past two years, this disease was located on holiday greenery coming into Minnesota. The Minnesota Department of Ag was able to locate the greenery and take care of the situation from there.

For more information on gardening, you can reach me at s.dejaeghere@me.com