Monday, February 29, 2016

Time to Start Watching for Weeds

The storms last week were a reminder that spring is on the way.  That means pastures will be greening as forages begin to put on spring growth.  After such a wet winter, hoof traffic has likely done some damage to your pastures no matter how careful you may have been, and that leaves areas with thin stands of forage, or even bare ground, where weeds will germinate.  In some areas, you may need to reseed, and now is the time for almost all of our common forages.  Check out the post from January 27 to choose the seed that is right for you.  No matter what though, some weeds will likely break through.  Often times I get called to identify a weed during the summer when they have reached 2 feet tall and are too large to treat.  The time to treat is in the spring when weeds are small and still actively growing.  Let’s take a look at a few common weeds with toxicity to horses.

Bulbous Buttercup
Buttercup

Buttercup is a winter annual, so it will be present now as a low growing weed with 3 parted leaves.  As spring arrives, it will begin to put on a thin stalk with a yellow flower.  These cause increased salivation, decreased appetite, colic and diarrhea.  In severe cases, poisoning can lead to convulsions and death.  Now is the time to control this weed before it puts on spring growth and flowers.




Cotyledon Stage Jimsonweed



Jimsonweed
Jimsonweed
A very common weed in our area that is often ignored until several feet tall.  Catching and treating this weed early will prevent it from putting on seeds and being a chronic problem.  Once large, the plant is easily identifiable by it’s tree like shape with purple, trumpet shaped flowers, and spiny seed pods.  To catch it early look for a weed germinating with initial cotyledons and leaves being long and slender, followed by leaves with a more jagged edge and triangular points down the leaf margin.  Crush a leaf in your hand, and there will be a strong smell that some folks compare to a raw potato.  Symptoms of poisoning include a weak but rapid pulse, dilated pupils, dry mouth, incoordination, diarrhea, convulsions, coma, and sometimes death.






Horse Nettle and other Nightshades
Horse Nettle
Horse nettle is the most easily identified of the nightshades.  It will be covered in spines on both leaves and stems.  Almost all of the nightshades will have a leaf structure similar to jimsonweed, with a triangular shape and jagged leaf margins, and many will have a purple tinge to the leaves, particularly on the underside.  Toxicity is highest in the green berries of Horse Nettle, but the entire plant is toxic, and spines can cause injury.  Some symptoms of nightshade poisoning include dilation of pupils, diarrhea, loss of appetite, and loss of muscular coordination.  You may also notice mood changes, such as depression or apparent hallucinations. 

Pokeweed

Pokeweed
Pokeweed is often found along fence lines and again is often ignored until several feet tall.  Small plants are easily identified by their large, oval, smooth leaves.  Many folks know this as poke salad, and some may even consume it.  Despite that, this weed does have many toxic properties that are more pronounced in older, mature plants.  The weed is not very palatable, and horses with access to a quality forage should avoid it.  It is still a good idea to keep fence lines clean and keep this weed out of your pastures.


Horses will prefer a quality forage over all of the weeds mentioned here, and will only be drawn to these weeds if options are limited.  Problems with toxic weeds often arise in times when forages are stressed from environmental conditions such as drought.  All of these weeds can be controlled with a broadleaf herbicide such as 2, 4-D or Dicamba, but remember these herbicides will also kill clover and alfalfa in a mixed pasture.  Talk to your extension agent for help identifying weeds and choosing the right control option for your situation. 

For more info on toxic plants, including toxic ornamentals, talk to your extension agent, or visit https://njaes.rutgers.edu/pubs/fs938/

Photos courtesy Virginia Tech Weed ID Guide, http://oak.ppws.vt.edu/~flessner/weedguide/