Lythrum alatum aka Angled Purple Loosestrife

Lythrum alatum is known as winged loosestrife. It is a perennial, a plant that lives for years. It is part of Lythraceae, the loosestrife family. The Royal Horticultural Society lists another common name: milkweed. Chicago Botanic Garden calls it a Midwest native. It grows in meadows and by shores in the wild. It is not native to Great Britain or Ireland. Thus, these records place it among native plants for Midwest gardens. They do not place it among Britain's native plants.

Plants grow upright to 2–3 feet [0.6–0.9 metres] tall. In gardens, they stay shorter than invasive purple loosestrife. The stems have four angles and hold small leaves. The leaves have broad bases and grow in opposite pairs. Small leaves grow among the flowers on the stems, too. The leaves can hide some of the blooms. This mix leaves the flowers less open to view.

The flowers have six petals and a magenta hue. Chicago Botanic Garden also classes their colors as pink and purple. Spikes of flowers rise at the tops of the plants. The garden's account says blooms start in June. Yet its wider bloom calendar runs from May through October. That span takes in late spring, summer, and part of fall. The source does not say why these two records differ. Neither account gives details of the fruit or seeds.

Chicago Botanic Garden lists full sun or part shade for garden growth. It calls for moist soil and gives USDA zones 3–9. Wild plants grow in both meadows and sites by shores. The garden lists beds and borders as uses. The plant's upright form and modest height suit these uses. The garden also notes that birds and butterflies visit. It does not name those species or say how they use the plant.

Do not confuse this plant with invasive purple loosestrife. Chicago Botanic Garden sets them apart and values this native plant. This alone does not show how much it spreads in gardens. The accounts give no width or rate of growth. They give no pest or disease details for this species. Neither source shows edible uses or safety for people and pets. These points remain unknown from the evidence given here.