Oklahoma is in the south-central region of the United States and has more than 2,500 types of soil. While this may make it somewhat of a challenge to establish a lush green lawn without a soil analysis, the common lawn weeds in Oklahoma like the variations in the soil just fine.
Bull thistle (Cirsium vulgare) is a herbaceous plant that can grow up to 7 feet tall. It has 3- to 12-inch lance-shaped leaves that have a jagged appearance and are quite hairy looking. From June to September, it produces 1- to 2-inch purple to purplish-pink feathery-looking flowers that sit atop spiny green bracts. The bull thistle can be controlled by removal in early spring before it blooms or with a post-emergent herbicide applied before the appearance of the first flowers.
Lambsquarter (Chenopodium album) is a summer annual can grow to 3-½-feet in height and has light green arrowhead-shaped leaves that grow 1-¼ to 10 inches in length. It produces clusters of tiny green flowers with no petals from June through September and has black seeds that germinate in late spring through the early summer. Lambsquarter can generally be controlled by mowing. However, if you are applying herbicide, a post-emergent should be used once the plant is growing but before the flower stage begins.
Wild geranium (Geranium carolinianum) is a biennial that can reach a height of 28-inches tall and sometimes grows as a summer or winter annual. It has ¾- to 2-½-inch wide green divided leaves that somewhat resemble parsley. Wild geranium produces small five-petal whitish-pink to purplish colored flowers and has an odd-shaped fruit that is thought to look like a stork's bill. If you are removing them by hand, single plants should be pulled or dug up before blooming, or they can be treated with a post-emergent herbicide during the growing stage and before the appearance of flowers.