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Deadlines/Dates
July 15: Deadline for Acreage Reporting
July 30: CRP/Kernza Field Day
August 15: Deadline to enroll in Emergency Commodity Assistance Program (ECAP)
How to Beat Invasive Weeds in CRP Plantings Without Harming Natives
Whether you’re restoring prairie, wetlands, or a pollinator paradise, CRP plantings often face their biggest threat not from drought or deer - but from aggressive weeds. Canada thistle, bromegrass, burdock, cottonwoods, wild parsnip, and their cohorts can outcompete your natives and reduce your habitat value fast.
The key: Targeted, well-timed weed control that works with native plant cycles - not against them. Below you will find a recommendation of common invasives in native plantings along with some general recommendations of control and timing.
1. Canada Thistle (Cirsium arvense)
This is a perennial spreader with creeping roots. The best method is to spray a herbicide with the active ingredient aminopyralid in June (bud stage) and reapply in September. You can also mow before flowering to limit seed. Spot spray is typically the best solution in native plantings, not broadcast spraying.
2. Musk/Bull Thistle
Both of these are Biennials. The best method is to spray a chemical with the active ingredient aminopyralid or 2,4-D at rosette stage (April or October). Pulling is also an effective method if done early. Ensure that the seed heads are disposed of to prevent further spread.
3. Smooth Brome (Bromus inermis)
This is a cool-season sod-forming grass. One of the best methods for control is to burn early spring (late March). Another method is to apply a herbicide with glyphosate in fall after natives go dormant.
4. Cottonwood & Green Ash Seedlings
These are common woody invaders we find in CRP plantings. It is best to use a herbicide with the active ingredient triclopyr, 20-25% in basal oil. Also, you can cut-stump treat in August-October or apply basal bark spray November-March.
5. Wild Parsnip (Pastinaca sativa)
This is a biennial with toxic sap. It is often best to use a herbicide with the active ingredient aminopyralid (in April-May or September-October. Mow before seed set in early July. Wear PPE; avoid burning dense patches.
Native-Friendly Tips:
- Use selective herbicides.
- Spray weeds when natives are dormant.
- Burn early for cool-season control.
- Spot spray to preserve diversity.
- Monitor annually. Weeds shift with time.
Final Thoughts:
Effective CRP weed control takes 3-5 years and a strategic approach. Always follow the herbicide labels. With persistence and proper timing, your native planting can thrive despite early invader pressure. Take the long view. The prairie doesn’t rush - and neither should you.
