The yellow flowering oxalis is a very common plant in our location here among the trees. It seems to prefer areas of moisture and shade. You can find it in lawns, gardens, waste places, fields, roadsides and open woodlands.
As kids we called the yellow-flowering oxalis “sour grass”. The seed pods are edible and taste a bit sour. I wonder if this is one of those things that big brother had me try first! Actually, it was probably just one of those things that people know about their own landscape, like what plants are edible and which aren’t. Some of this knowledge is passed on orally from generation to generation, but if it’s not in your experience, how would you know? Good thing you stopped by!
Oxalis herbs are also referred to as Wood Sorrels. The wood sorrels are marked by clover-like leaves in threes with each leaflet being heart-shaped. Yellow Wood Sorrel, Oxalis europaea, is an introduced species here in Pennsylvania and it’s native to Europe. There is also a pink flowering species, called Violet Wood Sorrel, Oxalis violacea, that I have not seen growing wild in our area of Pennsylvania.
Leaves are light green to maroon. When the plant has maroon leaves it makes the yellow blossoms really stand out.
Wood sorrel flowers have five petals and ten stamens and measure about a half-inch across. Oxalis flowers and leaves close up in the evening and re-open in the sunlight. Cloudy days will keep many Oxalis plants from opening their flowers at all.