Lady’s Thumb, Polygonum persicaria or Persicaria maculosa

and bacteria, and they help increase the deployment of white blood cells to areas of infection. Harvesting: Dig up the roots in autumn or leave them in the ground over the winter to harvest in the spring. Store them in high humidity to prevent them from wilting and softening. Tubers left in the ground will sprout in the spring. The tubers bruise easily and lose moisture quickly, so I usually prefer to leave them in the ground and harvest them when needed. Warning: Jerusalem Artichokes can cause digestive distress and excessive gas in some people.

Lady’s thumb, also known as smartweed, heart’s ease, spotted knotweed, or redshank, is a broadleaf weed that is often found growing in large clumps. It grows in disturbed wet soil across North America. It is in the Polygonaceae (Buckwheat/Knotweed) Family.

Polygonum persicaria by Bouba at French Wikipedia, photo by Bouba, CC-BY-SA-3.0-migrated

Identification: Lady’s thumb grows from 1 to 3 feet tall (0.3 meters to 0.9 meters) and is an erect plant. The 2 to 6-inch-long (5 cm to 17.5 cm) leaves are alternate, narrow, and lance-shaped with wavy edges. They usually, but not always, have a dark green to purple spot in the middle. Leaves may be hairless or covered sparsely with small stiff hairs. Leaf nodes are surrounded by a thin papery membrane that wraps around the stem. The small, dark pink, (rarely white) flowers are densely packed in 1-inch (2.5 cm) spiked terminal clusters. They spike open, while those of the pale look-alike smartweed remain closed (pale smartweed also lacks the purple leaf smudge). Each bloom is approximately 1/8 inch (0.35 cm) across with five petals. Fruits are brown to black and glossy. They have three sides and are eggshaped. Each fruit contains one tiny seed. Edible Use: The leaves and young shoots can be eaten raw or cooked. Gather young leaves and sprouts in the spring to mid-summer. As they mature, they become more peppery and less palatable. The seeds are also edible, but they are rather small and require a lot of work to harvest enough to make a serving. Medicinal Use: Use as a tea, decoction, or by applying the leaves directly to the skin. Stomach Pains: For stomach pain and digestive upset, drink a leaf tea.

Stem of Lady's Thumb, Martin Olsson, CC by SA 3.0

Skin Ailments: Lady’s thumb is a rubefacient, and thus increases blood circulation at the skin’s surface, supporting healing. It is also an astringent. Use for poison ivy, poison oak, skin rashes, and other skin ailments. Rub the crushed leaves on the skin or put a poultice on the surface of the skin. Arthritis: For arthritic pain, soak in a tub of warm water containing a decoction of lady’s thumb. The decoction can also be mixed with flour to form a wet poultice to help relieve painful joints.