When spring soil temps (at a depth of 2"-3") reach 55-60 degrees Fahrenheit, the first crabgrass seed will germinate. From mid-summer to fall, seeds are produced. The plants, themselves (but not the seeds) are killed by frosts in autumn.
Yellow Nutsedge (Cyperus esculentus L.)
Yellow Nutsedge (Cyperus esculentus L.) is a common weed found in many home lawns and other turf grass areas. The color, growth habit, and rapid growth rate make yellow nutsedge a prominent distraction in the aesthetics of high quality lawns.
Yellow nutsedge is distinctive and relatively easy to identify. The stems are erect, triangular-shaped and yellow-green in color. The leaves are also yellow-green, wide (0.38 to 0.50 inch) bladed with a thick mid-vein and a very waxy covering. The shallow, fibrous root system often produces many nut-like tubers, which are underground food storage organs. Each of these tubers can germinate and produce new plants. Each new plant can also produce rhizomes which can give rise to additional new plants.
Wild Violet (P) — Viola papilionacea
Wild violet is a low-growing clumping perennial with a dense, fibrous root system and heart-shaped leaves that often cup toward the petiole to form a funnel shape. Wild violet is often considered difficult-to-control due to its aggressive growth, waxy leaves and resistance to most common herbicides.
Wild violet is most often found in shaded, fertile sites and prefers moist soils.
Flowers occurs in mid-May; usually violet colored, but can vary from deep-blue-violet to completely white. Plants spread by rhizomes and seed.