Winter is a wonderful time to reflect on the activities of the passing year and to plan for the coming growing season. Always near the forefront of planning activities for the Wildflower Garden are matters related to management of the native plant collections. To care for the health of the Wildflower Garden’s native plants, a focus on removal of troublesome plants is inherent. Weed management at the Wildflower Garden is a dynamic and evolving practice, part science and part art. Deciding which plants will go and which will stay is a process that requires a continuous interaction with what is unfolding in the plant collections.

Non-native Invasive Species

There are four broad categories of undesirable plants at the Wildflower Garden, and they fall along a spectrum. The first, and most unwanted, are the non-native invasive species with which many of us are quite familiar. Buckthorn, garlic mustard and Japanese knotweed are all invasive plants that have a mind of their own and can, in a matter of years, run rampant throughout a garden area if afforded the chance. Our goal is to eradicate the non-native invasives.

Non-native Aggressive Species

The second group is made up of non-native plants that aren’t going to completely take over a given garden area in a brief time period but will aggressively spread and eventually negatively impact the plant collections. These plants can move into non-edge zones of the Wildflower Garden, and their impact will be felt and seen over time. Our goal for this group, which includes such plant species as moneywort, periwinkle and Ohio buckeye, is to limit them to manageable populations near trails for display and educational purposes.

Non-native Weeds

Then there are the common non-native weeds that prefer disturbed habitats, typically along trail edges and newly tilled soil or areas where extensive weeding and invasive species removal has occurred. The weeds in this third group won’t compete well with most established plants; their spread is limited to disturbed sites and edge areas found in the Wildflower Garden. These familiar weeds of home landscapes include European bellflower, common dandelion and red clover. Our goal is to limit this group to manageable populations near trails for display and educational purposes.

Native Weeds

Finally, there are the aggressive native plants. In the Wildflower Garden, there are a handful of plant species that, although native, tend to be vigorous growers, to a fault. These plants typically spread by rhizomes or seed and over time can be just as damaging to the diversity of the plant collections as some of the non-native aggressive plants. Good examples of plants in this fourth category include early goldenrod, jewelweed and prairie cordgrass. Again, our goal is to limit this group to manageable populations near trails for display and educational purposes.

Several different control methods are used to manage invasive species at the Wildflower Garden. If multiple control methods work for a given species, staff members will choose the least harmful and most effective approach. Sometimes control involves the use of more than one method for a given species over time. These control methods include manual removal, use of direct high-heat flame, controlled burns, biocontrol and herbicides.

All invasive and weed species are dealt with on a case by case basis, as no two are exactly alike. Generally, the more aggressive a given plant species is, the more immediate the need for its removal.

Decisions about which plants will go and how they will be removed or controlled is an ongoing process—one that requires a dynamic and responsive management approach.