Weed Management for Wild Blueberry
Fact Sheet No. 239, UMaine Extension No. 2025
NOTICE: It is unlawful to use any pesticide for other than the registered use. Read and follow the label on the product container. The user assumes all responsibility for a use inconsistent with the label.
This fact sheet is to be used only during 2019. Use in subsequent years may lead to improper and illegal use of pesticides. When this guide is outdated, please request an updated version from your Extension office or on the Maine Wild Blueberries website.
WARNING! Pesticides are potentially hazardous. Handle carefully! Read and follow all directions and precautions on labels. Store in original labeled containers out of reach of children, pets, and livestock. Dispose of empty containers at once, in a safe manner and place. Do not contaminate forage, streams, ponds or groundwater recharge areas.
Why Manage Weeds?
Why Culturally Manage Weeds? To increase yield and reduce pesticide exposure to off-target organisms such as bees.
Weeds Compete with Wild Blueberry for:
- Water
- Light
- Nutrients
The method for controlling one weed – may encourage another. A combination of careful ID and monitoring of the weed situation in a field, with cultural management and the wise use of herbicides (only when critical) forms the basis of a sound weed management program.
THERE IS NO QUICK FIX. One method will not control all weeds.
Cultural weed control: routine management practices that can prevent pests from developing in the first place.
Chemical weed control: involve the use of naturally derived or synthetic chemicals (pesticides) to kill, attract, repel or otherwise control the growth of pest plants, animals and microorganisms.
The table below includes pre-emergence and post-emergence herbicides commonly used for specific weeds or types of weeds in wild blueberry fields in Maine. The selection of herbicides should be made on the basis of what specific weed species are present in the field.
Pre-emergence herbicide rates are based on the amount of commercial product per acre or the percent solution for spot treatment. To achieve good weed control application, equipment must be calibrated so that the required amount is applied accurately and uniformly. Under application may result in poor weed control and over application can cause severe crop injury.
Post-emergence non-selective herbicides listed for herbaceous weeds, some herbicides for woody weeds applied to weed foliage with wiper applicators, and selective post-emergence herbicides should be applied at the proper stage of weed growth.
Post-emergence grass herbicides are selective, so may be applied as a broadcast spray when grasses are small without injury to blueberries, but are more effective as a spot treatment.
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Cultural Weed Management Practices for Wild Blueberry |
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Weeds Controlled |
Method |
Comments |
| Most weeds, especially grasses | Test soil for pH and reduce with sulfur if above 4.0 |
Add nitrogen or phosphorus fertilizer only if leaf analysis indicates a deficiency.
Maintain soil pH at 4.0. |
| Most weeds except grasses | Hand pulling |
Effective against spot infestations.
Pull before any weed flowers go to seed. |
| Weeds spread by seed or vegetative parts carried on equipment, especially mechanical harvesters | Field sanitation | Steam clean and inspect equipment before entering a field. |
| Bracken fern, sweet fern, dogbane, seedling or sprouting trees, flowering weeds | Mowing above blueberry plants |
Most successful if done during the vegetative year.
Cut flowers off before they go to seed. |
| Coniferous trees, some weeds spread by seed | Fire pruning | When burning with straw or hay, use weed-free material. |
| Weeds that form crowns at or above ground level | Cut or mow woody weeds three times in the non-crop year | Mow or cut plants to ground level. |
| Some of the weeds spread by seed | Mulching on bare spots |
Apply mulch 2″ to 4″ deep.
Use one of the following: bark, woodchips, shavings, sawdust, peat or sand. |
Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.
© 2022
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