Yellow Wood Sorel (Oxalis stricta)
Wood sorel is a common ground cover found in most parts of the Midwest. It especially thrives in degraded habitats, so it should be easy for the wandering survivor to find in deforested areas along power lines, along roadsides, in abandoned gardens, etc.
The leaves of wood sorel are edible and have a sweet to sour taste. They also contain Vitamin C, which may become a rare nutrient for post-apocalyptic survivors once stockpiles of fruit and juice have diminished.
Of Note to Pre-Apocalyptic Plant People:
Herbacious perennial that can get 6 inches to a foot tall. The leaves are trifoliate, heart-shaped, and fold up when in full sunlight. Yellow bell-shaped flowers with five petals emerge from the leaves, sometimes with a red center.
Very common plant found in many habitats, including woodland clearings, mesic black soil prairies, savannas, limestone glades, fields, lawns, edges of paths and driveways, and waste areas.
Full or partial sun. Prefers rich loamy soil, but can tolerate clay, gravel, and sand. Prefers moist to slightly dry conditions. Cannot tolerate hot and dry parts of mid summer and becomes dormant during these conditions.
Wood sorel is very ubiquitous and often not considered in design, although it could be used as a ground cover with some yellow coloring from its flowers. Wood sorel is not often planted; it spreads easily.