Identifying and treating invasive species in the spring

With the recent Safer at Home Act many of us are looking for ways to pass the time and keep our children and families active and healthy. What better way to pass the time than to learn how to identify invasive species, begin planning control methods, and gathering garlic mustard if it is present on your property? In this article I will discuss, and provide resources on:

  • the importance of identifying invasive species in your woodlands in early spring
  • popular control methods for woodland owners
  • best practices to stop the spread of invasive species
  • a recipe that uses garlic mustard (common in Wisconsin) to make a tasty garlic pesto!

Spring is in the air… well, sort of. In the southern half of the state many of us are starting to see greenery popping up in our yards and woodlands. Seeing this is a positive reminder that spring is here and soon we will look out our windows to see lush grasses and leaves on trees. For woodland owners, this may also be a reminder to get out and survey your woodlands for invasive species. This is the best time to look for invasives because they will be green before the native grasses and shrubs on the forest floor.

Invasive species impact yards and woodlands by spreading rapidly via roadways, hiking boots, ATV tires, wildlife droppings, and wind carry. This rapid spread (and the lack of natural native controls) allows them to outcompete native vegetation, prevent forest regeneration, alter and damage ecosystems, modify soil composition, and alter/degrade wildlife habitat. Smokey Bear tells us that only we can stop wildfire, and the same is true for invasive species. We as woodland owners are responsible for stopping the invasion and spread on our lands.

I recently spoke with Chris Gaetzke, Executive Director of The Lower Chippewa Invasives Partnership, Inc (LCIP). He shared their website which has a useful link to identify 6 common invasive species found statewide in Wisconsin: common buckthorn, wild parsnip, garlic mustard, spotted knapweed, Japanese knotweed, and leafy spurge. If you’d prefer to watch some short videos, LCIP has a series of videos of short videos of invasives and native species from a spring survey.  You can find those videos here. UW-Extension Weed Science also has several short videos to help you identify these common invasives, and others that are found across the state. You can find those videos here. The Invasive Plants Association of Wisconsin website is another great resource to learn more about identification and controlling invasive species in your woodlands.

It is always a good idea to walk your property and keep an eye out for new invasive plants and to monitor infestations that already exist. The Wisconsin DNR provides a brief overview to woody invasive species control techniques with guidance on which methods to use in specific site conditions.

Some of the most popular methods to control invasive species are manual, mechanical, and chemical control. Manual control includes hand pulling shoots and digging up roots and smothering large areas with black plastic or mesh materials. Common mechanical techniques include cutting, girdling (woody invasives), and mowing large areas of spread. Chemical control is often used in with manual or mechanical control, and includes basal bark treatments, cut stump, hack and squirt, and foliar spraying. Spring is a great time to survey and mark target invasive species. Then follow up with manual control and herbicide treatment after all the leaves have fully grown. At that time the plants are not pushing nutrients up to the plant which happens in the spring and leaves herbicides ineffective.

Persistence is needed to work on spring invasives. Check out this story from a fellow Natural Resources Educator, Bill Klase. Here he shares his experiences controlling buckthorn on his property, which had gone unnoticed for a few years and successfully spread. Some species like buckthorn take years to control, which is why preventative measures are crucial.

One of the things Gaetzke mentioned was how to prevent the spread of invasive species. His key takeaway message was “5 minutes of prevention now can save thousands of dollars down the road in control.” Here are some tips on how to accomplish 5 minutes of prevention to stop the spread of invasives on your woodlands:

  • Always clean your shoes with a boot brush before going out, or before moving from one site to another, in your woodland. You can use a handheld or step-on brush to dig out the dirt, soil, debris, and seeds from the previous year. If you use an ATV or other vehicle be sure to pressure (or hose) wash the tires before you start exploring the trails. Tires can carry old dirt, soil, debris and seeds just like the bottom of your boots. You can carry a handheld brush/horse pick in your day pack or stash it on your ATV.
  • If you lease your land or allow friends to spring hunt on your property (turkey, sheds, or morels) ask them to brush their boots before they go out onto your property. Garlic mustard will be sprouting at that time and boots are a great way for seeds to travel.
  • Be diligent in walking your woods in the spring to check for invasive species. Although you may not catch every plant, you will have a better handle on the sizable infestations and be able to control them before they continue to spread and cause damage to your woods. Also remember to do tick checks after walking your woods. Protecting your health is just as important as protecting the health of your woods.
  • Continue to monitor your invasive sites over time. Take before and after photos and use a compass or your phone and property map to take notes on the site: what species you found, what year you first noticed it, treatment types and dates of treatment, etc. Use this year after year to track the changes in your woods and use it as a pat on the back for all your hard work!

The most satisfying revenge you can take on some of these pesky, invasive plants is to eat them. Gaetzke shared a tasty recipe that gives you a way to use those pesky garlic mustard plants you pull from your woodlands. Although I haven’t tried the recipe yet, I am a fan of pesto and fresh baked bread and am planning to make this for a summer potluck. Consider trying this recipe that freezes well to make for a dish to pass once we are able to reunite with our friends, coworkers, neighbors, and families!