ArborActive Tree Care Guide
How to Control Garlic Mustard in CT, MA & RI
By ArborActive Team · Updated
A flowering patch is easy to spot, but first-year rosettes and seed already in the soil can keep the infestation going.
Identify the plant
Alliaria petiolata. First-year plants form low rosettes with rounded, scalloped leaves. Second-year stems carry triangular toothed leaves and small white flowers with four petals. Crushed leaves may smell of garlic.
University of Connecticut Extension identification and management guideChoose a control method
Start with the size of the patch, what you want to preserve and whether the site is near water.
Small patches
Pull plants before seed pods mature, removing the root where practical. Minimize disturbance to nearby native plants. Bag flowering or seed-bearing material and check local disposal instructions because pulled plants may still produce seed.
Established infestations
Work from isolated plants toward the main patch and revisit the area. Cutting flowering stems can reduce seed production when timed and repeated appropriately. Where rosettes form dense patches, a qualified applicator may assess selective treatment that avoids desirable plants.
Keep it from coming back
Return each spring to find flowering plants and check later for rosettes. Clean soil and seeds from boots and tools before moving to another area. Continue monitoring after the first season with little visible growth.
Check local requirements
Before moving plant material, working near water or using an herbicide, check the rules for your property. Use only products labeled for the plant and site, and follow the label. Ask the local authority about disposal.
Connecticut invasive plant list
Check the current regional guidance before work.
Connecticut invasive plant listMassachusetts prohibited plant list
Check the current regional guidance before work.
Massachusetts prohibited plant listRhode Island invasive species resources
Check the current regional guidance before work.
Rhode Island invasive species resources
Common questions
Why did it come back after I pulled it all?
Seeds from earlier years can germinate after visible plants are gone. A return visit is part of controlling the patch.
Ask ArborActive about your property
Send your town, the approximate patch size and a photo of the suspected garlic mustard. Mention nearby water and plants you want to keep.