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Weeds & Invasive Plants

All Weeds & Invasive Plants Content

Young farmer analyzing data on a tablet computer beside a crop sprayer.
Dec      Feb 03 - 28

2026 Commercial Applicator Training Online Course

SDSU Extension partners with DANR to offer pesticide certification program required for commercial applicators. The 2026 online course will be offered through Traininghouse and will be open from December 3, 2025, through February 28, 2026.

Gloved hands examining a musk thistle seedhead.

Now is the Time to Plan for Noxious Weed Control in 2026

Most of South Dakota experienced first frosts that were delayed by at least one month, allowing for noxious weed growth to continue later in the season. Now is the time to plan for noxious weed management tactics.

Snow-dusted, harvested field with a few scattered plants throughout.

Now is the Time to Prepare Your Weed Management Plan for the 2026 Growing Season

As harvest season comes to an end, now is the time to start formulating your weed management plan for next year. Learn some expert tips for getting your operation off to a good start this coming growing season.

Spaying fertilizer or chemical on plants
Feb 25

Commercial Ornamental/Turf Applicator Training @ Rapid City

SDSU Extension will host ornamental and turf commercial applicator training in Rapid City at the Ramkota (2111 N LaCrosse St, Rapid City, SD 57701) on February 25, 2026, from 9:30 a.m. – 4:30 p.m. MT.

Crop duster over a corn field
Feb 19

Commercial Aerial Applicator Training @ Tri-State Aerial Applicators Convention

SDSU Extension, NDSU Extension, and UMN Extension will host a joint aerial commercial applicator training on February 19, 2026, from 11:45 a.m. - 2:15 p.m. CST in conjunction with the Tri-State Aerial Applicators Convention, which will be held at The Delta Hotel in the Symphony Hall (1635 42nd St SW, Fargo, ND 58103).

Canada thistle growing in a pasture.

Noxious and Pasture Weed Plot Data Report

Data books to use as a reference to select appropriate herbicide(s) for noxious and pasture weed

Examples of Wild violet, Creeping Bellflower, and Ground Ivy growing on a lawn.

Perennial Weed Control in Lawns and Turf With Fall Herbicide Applications

Early fall is great time to control perennial weeds in lawns, including Wild violet, Creeping Bellflower, Ground Ivy, and Canada Thistle. Learn some expert tips selecting the right herbicides to manage these difficult-to-control weeds this fall.

Yellow toadflax plants flowering in a grassy area beside a field.

Yellow Toadflax Has Begun Producing Seeds: Scout before treating infested areas

Yellow toadflax is a perennial weed that infests pasture and rangeland across South Dakota. This year, with an abundance of heat and moisture, plants flowered in early August and now have started to produce seeds.

Gardeners browsing a tablet computer while visiting a garden center.

Home Horticulture Resources for Gardeners

Horticulture is the branch of plant agriculture dealing with garden crops. In addition to our website, there are many horticulture resources available on the web to provide research-based information to help every gardener succeed.

A green Palmer amaranth weed surrounded by various other green plants.

Palmer Amaranth Confirmed in Turner County: Is this weed in your fields?

Palmer amaranth has recently been confirmed in Turner County. Currently, the estimation of Palmer amaranth infestations has been confirmed in 18 counties across South Dakota