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Tuesday - November 06, 2012

From: Harwood, TX
Region: Southwest
Topic: Plant Identification, Problem Plants
Title: Identity of yellow-flowered plant with stickers
Answered by: Nan Hampton

QUESTION:

I have yellow flowered plant taking over my lawn. I used weed killers last year and it has spread this year and still spreading. It has small burs (not as hard as a regular sticker bur but will stick in your foot or hand. What is it and how do I get rid of it?

ANSWER:

The best possibility for your weed, I think, is one of the burclovers. One with particularly prickly seeds is Medicago polymorpha [syn. = Medicago hispida] (California burclover). It was introduced from Europe and is commonly used as a forage or cover crop for livestock. It also is a nitrogen fixer that enhances nitrogen availability in the soil. However, even though sheep eat it, the prickly seeds tend to get caught in the sheep's wool and lower the value of the wool. It is considered invasive in many places as it spreads through lawns and other unwanted areas. You can see on the general distribution map from the USDA Plants Database that it occurs over most of North America. Although it is not shown as occurring in Gonzales County on the Texas County Distribution map, it is shown as occurring in counties surrounding Gonzales County. You can read from Dr. Kaae-Online an extensive article on various methods to control it that are based on the University of California Online IPM Programs. As you know, it isn't easy to control and you will need to use a combination of methods and be persistent.

Another possibility for your plant is Tribulus terrestris (Puncture vine), a native of temperate and tropical areas of the Old World. However, its seeds are quite formidable and have been known to puncture tires so I doubt that this is your weed.