Chemical control of any weed is most effective when they are in an immature growth stage
I’ve been doing a lot of driving through the county this week and have noticed a plethora of yellow-flowered weeds.
What are they?
Well, unfortunately most of them have ben cressleaf groundsel (CG), a poisonous weed that has made its way onto the Ohio Noxious Weed list that is published in the Ohio Administrative Code.
More: Fungicide use for homeowners
Cressleaf groundsel, along with its 30 counterparts, are required by law to be controlled to prevent further spread.
Roadside vegetation must be mowed back or sprayed at minimum during the dates of June 1 through 20 and Aug. 1 through 20.
Chemical control of any weed is most effective when they are in an immature growth stage and still relatively small.
Controlling CG can be difficult because of its biology. It is a winter annual, meaning it germinates in the fall, continues to grow all winter, then blooms in early spring.
With some agronomic fields looking like pure stands of the yellow, daisy-like flower, a burndown approach may be warranted early in the season.
Herbicides can control weeds in the fall in grass hay fields or pastures
Chemical options for control in the fall in grass hay fields or pastures include herbicide products that contain 2,4-D. If control is necessary in an alfalfa field or a grass/alfalfa mix, options are limited but include Sencor 75DF, Velpar, Pursuit, and Glyphosate (spot treatments only).
Widespread control may especially be of interest to those making hay in addition to growing corn or beans. With the ease of which the CG seeds spread, an infestation can quickly pop up in a hay field or pasture.
While grazing animals will not typically seek out the CG or other poisonous weeds, the animals can potentially be “starved” into eating them when no other vegetation is available.
Like other poisonous weeds, the ensiling or hay making process does not destroy the toxins (pyrrolizidine alkaloids) in the plant tissue and the stored forage can still poison an animal.
When making hay in a field where CG is present, the occasional plant is not going to destroy a whole cutting. However, heavy infestations are not advised to be cut and made into hay.
You may brush hog the vegetation down and wait for the next cutting when CG is not present (end of June through August, at least). Keep in mind the seeds will germinate in the fall, so scout hay fields for late season cuttings to ensure you’re not baling young rosettes.
Some other weeds with yellow flowers blooming this time of year
There are other weeds with yellow flowers that are blooming this time of year, including yellow rocket, greater celandine, and little leaf buttercup.
Yellow rocket is very common in Ohio. With its small cluster of yellow flowers, from a distance may look like CG, but the leaves are different in shape.
Greater celandine also has small yellow flowers, but they are not clustered. It produces a yellow sap when the stem is broken.
Little leaf buttercup is a yellow flower with 5 small petals that resemble a star when fully bloomed. They are on relatively leafless stems, but the leaves that are present have 3 differing shapes depending on their location on the stalk.
If you need help identifying a yellow-flowered weed, bring it in to the office, snap a photo and send us an email, or download a plant ID app on your smartphone. We’d be glad to help you out!
Upcoming events
A Forages for Horses Pasture Walk will be held on Tuesday, June 7 from 6 to 8 p.m. at the ATI Equine Facility. Topics will include fescue toxicosis and poisonous weeds, rotational grazing, and pasture evaluation. Dinner will be provided. Registration is requested for preparation of materials and catering. Cost to attend is $15 if registered by June 1 and $20 if registered between June 1 and June 6. Please call 330-264-8722 to register.
Wayne County Extension will be hosting a Small Grains Field Day on Tuesday, June 14 from 8:30 a.m. to 2:30 p.m. Topics covered will include wheat cultivars, disease identification and management, cereal leaf beetle management and much more! The event is free thanks to the generosity of the Ohio Corn and Wheat Board but we ask that you register by June 7 for catering orders.
Please call 330-264-8722 to register or head to go.osu.edu/small-grains-field-day.
This article originally appeared on The Daily Record: Haley Zynda: What are those yellow weeds?
