Field Guide
When to Remove Invasive Plants in Central Ohio
The best time to remove an invasive plant depends on what it is and how you plan to remove it. Across the Upper Scioto watershed and the 17 counties of Central Ohio, the seasons offer different windows for cutting, digging, and treating our most common invasive species. This calendar breaks down the timing for each season.
Late Fall and Early Winter
After the first hard frost, usually by late November in the Columbus metro area, native plants have dropped their leaves and moved resources below ground. This is when bush honeysuckle shows itself most clearly. The deciduous shrub keeps its leaves longer than most natives, making it stand out in the gray November landscape. If you can see it, you can cut it.
A sharp saw or pruning shears work well for cutting; aim for a cut below the soil line to prevent regrowth, though you may need to retreat stumps with herbicide the following spring. Late fall is also when you can spot invasive vines like Oriental bittersweet clinging to trees and shrubs along streambanks and forest edges throughout our region. The bare branches make removal easier and less damaging to plants below.
Late Winter and Early Spring
Late winter, February through early March, before bud break, is the best time for chemical treatment of woody invasives like Callery pear and bush honeysuckle. The plants are still dormant, and sap has moved down to the roots. A basal bark treatment (applying herbicide to the cut stump or lower trunk) or a cut-stump treatment works most effectively now because the plant cannot actively defend itself with new growth.
Energy is not being wasted on new leaves; instead, the herbicide travels directly to the root system. For detailed guidance on Callery pear removal, see our species guide. This is also when you can pull or dig first-year garlic mustard rosettes if you spot them. The soil is often softer from snowmelt, and removing small rosettes now prevents spring flowering and seed set.
Spring
As the soil warms in April and May, garlic mustard shifts into its second year of growth and begins to bolt, sending up flowering stalks. Second-year plants are much larger and have deeper roots, making them harder to pull cleanly. If you missed the first year, pulling these plants as soon as they flower (before seed pods mature) is your next best option.
The key is preventing seed production; garlic mustard seeds can remain viable in the soil for many years, germinating whenever conditions allow. Spring is also when Japanese knotweed emerges along the Olentangy, Scioto, and other waterways in our region. The young shoots are still soft and manageable, though the plant will continue to expand throughout the growing season. Early-season monitoring helps you track where the largest patches establish themselves, so you can plan summer management.
Summer
Summer heat and long photoperiods favor actively growing plants, including invasive species. Japanese knotweed spreads aggressively during summer months, especially along streambanks and disturbed areas. If you are monitoring infestations for the first time, summer is when they are most visible and most actively establishing themselves.
Summer is also a good time to scout for other invasive perennials, such as dame's rocket and multiflora rose, which are in full bloom and easy to locate in fields and along roadsides. Noting their locations now helps you prioritize management for fall or the following season. Document what you find; these observations guide long-term stewardship across the Upper Scioto watershed.
Fall
As autumn approaches and day length shortens, many invasive plants begin to slow growth. Fall is an ideal time to return to late-season garlic mustard plants that flowered in spring and summer; by then, their seed pods have ripened and will continue to spread seed as you remove them, so timing and careful disposal matter. If you must remove mature plants, do so carefully and do not leave cut material on the ground where seeds can continue to disperse.
Fall is also when Callery pear fruits ripen and birds spread the seeds throughout the region. Fall removal prevents new seedlings from establishing the following year, though chemical treatment in dormant season is more effective. Use fall to scout and plan for your late-winter removal work.
| Season | Primary task | Species |
|---|---|---|
| Late fall | Cut while visible; cut below soil line | Bush honeysuckle, Oriental bittersweet |
| Late winter | Chemical treatment (basal bark or cut-stump) | Callery pear, bush honeysuckle |
| Spring | Pull/dig first-year plants or prevent seeding | Garlic mustard, Japanese knotweed (early scout) |
| Summer | Monitor and document for future removal | Japanese knotweed, dame's rocket, multiflora rose |
| Fall | Scout locations; remove plants before dispersal | Callery pear, garlic mustard |
Frequently Asked Questions
What is the best time of year to remove invasive plants?
There is no single best time for all species. Removal timing depends on the plant's life cycle and your method. For woody invasives like Callery pear and bush honeysuckle, late winter offers the best window for chemical treatment because the plants are dormant and will absorb herbicide into the root system. For herbaceous invasives like garlic mustard, early spring (targeting first-year rosettes) or early flowering (before seeds mature) offers the highest success rate. Japanese knotweed requires repeated monitoring and management throughout the growing season. The common thread: remove plants before they flower and set seed, whenever possible.
When should I cut bush honeysuckle?
Cut bush honeysuckle after the first hard frost in late fall or early winter, when native plants have dropped their leaves and honeysuckle still has foliage. This makes it visible and easier to target precisely. Cut the stem as close to the soil line as possible. If you cut in fall or winter, plan to monitor and treat stumps with herbicide in late winter or early spring to prevent regrowth; many invasive honeysuckle stems will try to regenerate from the stump. Do not leave cut branches on the ground; chip them or remove them from the site entirely to prevent new root establishment.
When do I pull garlic mustard?
Pull garlic mustard in early spring, ideally in late March or early April before the plants flower and set seed. Look for first-year rosettes, small, low clusters of wavy-edged leaves close to the ground. These are much easier to pull than mature plants and come out cleanly if the soil is moist. If you miss first-year plants and they have already bolted, pull them as soon as you spot them before seed pods mature. Timing matters: pulling mature plants and leaving them on the ground spreads their seeds across the landscape. Always bag or remove cut material entirely from the site.
Start with your watershed
The Upper Scioto watershed spans 17 counties across Central Ohio, from the Olentangy and Scioto rivers to dozens of tributaries and wetlands. Every stream, meadow, and forest margin in this region holds invasive plants. The best removal strategy is one you can repeat, knowing your site, knowing your plants, and removing them at the right moment in their life cycle.
Use this calendar to plan your own removal work or to support the volunteer stewardship already underway across the region. For specific guidance on native plants that thrive in Central Ohio and can replace the invasives you remove, see our guide to native alternatives.