Timing Is Everything With Weeds!

— Written By and last updated by Leeann Crump
The weed, Dog Fennel, growing in a pasture.

The weed, Dog Fennel, growing in a pasture.

Several Farmers have gotten proactive in pasture and hay management this year. They have been scouting their fields, bringing in their unknown weeds for identification, and working towards a weed management plan. Weeds are a huge problem, because they take light, water, and nutrients away from the desired species. Some weeds also are poisonous to animals and can become an issue if desired forages are limited. This can occur during periods of drought especially. Normally, animals that are fed a balanced diet will taste a poisonous weed and remember that it didn’t taste good the next time and just walk around it.

I get excited when farmers bring weeds in around March, April, and May because I can help them with a good solution. The problem comes in July, when people pull up big stalks of dog fennel that are waste high and ask for control solutions. Weeds are controlled when they are small and by the time they are more than a few inches tall, controlling them is very difficult and sometimes impossible. Always follow the label when spraying for weeds, not only because it is the law to do so, but also because it will tell you what growth stage, time of year, potential damage to nearby sensitive crops, and waiting period after treatment to use the forage. Many herbicides require you to remove animals from the pasture for 7-14 days for their own safety.

Once weeds get too tall, the only control measure left at that stage may be to mow the weed before it gets a seedhead on it to prevent future plants from growing. However, many low growing weeds such as goosegrass, dandelion, and nimblewill cannot be controlled by mowing. Many weeds such as prickly pear and wooly mullein may need to be dug up with a shovel because it is difficult for herbicides to get through their thick leaves.

There are also several other ways to help with weed management. Some weeds thrive at low fertility levels, so you definitely want to take a soil sample to see what fertilizer and lime your fields need. However, adding lime and fertilizer alone are usually not effective in getting rid of all weeds. Some weeds like chickweed and curly dock do better in fertile soil, so you will want to control weeds, before fertilizing and liming. Also, if you overgraze animals on the target grass, weeds can overtake the pasture before the desirable grass has time to recover. It’s a good idea to split your fields up with temporary fencing and let animals graze in one small area at a time to let the other areas recover. You will also get more out of your grass managing a pasture in this way. Goats will eat many weeds and are able to get a lot of protein out of them such as from kudzu. For this reason, many farmers put a few goats per cow on their pastures in order to control weeds.

For additional information on weed control in pastures and hayfields, please contact Tiffanee Conrad, Agricultural Extension Agent at 997-8255 or email at tiff_conrad@ncsu.edu. If you have questions about the weeds in your lawn, please call our office or email Paige_Burns@ncsu.edu. Lawns actually have more flexibility for control because animals are not eating it.