Oxalis Species, Slender Yellow Wood Sorrel

The zone information is incomplete.... These little things will grow even in zone 3.

It's resistant to most herbivorous a...Read Morend omnivorous wildlife -- because it's toxic to them if eaten in large quantities, so, while grazers do nibble, usually eating the little flowers, they don't consume major amts. The plant is, however, invaluable to early appearing pollinators like honeybees in cold zones as they are among the group of early blooming flowers.

Also of note.... All parts of the plant are edible, with a distinct tangy flavor (common to all plants in the genus Oxalis). However, it should only be eaten in small quantities, since oxalic acid is an antinutrient and can inhibit the body's absorption supply of calcium. Granted, most healthy foods (nuts, grains, veggies) contain some form of antinutrient....

According to the USDA, this is native to the continental United States.
...Read More" target="_dgnew"rel="nofollow">http://plants.usda.gov/core/profile?symbol=OXDI2

This alone will now cause me to leave it alone. We are out in the country and surrounded by industrial crops. Once we learn something is a native, we will let it go on our 9 acres of land. We've started noticing deer on our property recently and the above link mentions, this plant is moderately consumed by large mammals. If there is enough of this for them to eat, just maybe they will stay away from the people food gardens.

This Yellow Wood Sorrel (O. dillenii) is a European introduction to North America. I don't like it simply because it's not native to my a...Read Morerea. It has seed capsules on reflexed stalks.

Look-alikes include:
O. stricta - This perennial plant is native to U.S. and Canada and is usually about 6" tall, but sometimes reaches 1' or a little more. There is a central stem that branches occasionally, creating a bushy effect on mature plants. It is often covered with scattered white hairs. The alternate trifoliate leaves have fairly long petioles, and are about ¾" across when fully open. Depending on environmental conditions, they are light green, green, or reddish green, and fold up at night. Occasionally, they fold up in response to intense sunlight during midday.

Floppy umbels of yellow flowers emerge from the leaf axils on long, slightly hairy stalks. Each bell-shaped flower is about ½" across when fully open, and has 5 petals that flare outward. There are fine lines toward the throat of the flower, which is subtended by 5 green triangular sepals. Sometimes, the throat of the flower is slightly red. Like the leaves, the flowers close-up at night. There is little or no floral scent. The blooming period peaks during late spring or early summer, but continues intermittently until the fall. Plants often become dormant during the hot dry spells of mid- to late summer. The root system consists of a slender branching taproot with numerous secondary roots. This plant spreads by means of mechanical ejection of the seeds from the slightly hairy elongated seed capsules; each capsule splits into 5 sections.

O. grandis - Large Yellow Wood Sorrel has flowers to 1 (2.5 cm) wide and leaves often with purple edges; it is native and grows from Indiana east to Pennsylvania and south to Georgia and Louisiana.

This plant also grows wild in Louisiana. You can see them in abandoned lotts, with other clover plants.