Yellow milkwort flower

Yellow milkwort

Pictured above: Yellow milkwort (Polygala rugelli) by John Moran. Click on terms for botanical definitions. View post as a PDF.

Also known as Rugel’s milkwort, Yellow milkwort (Polygala rugelii) is an annual herbaceous wildflower endemic to the Florida peninsula. It occurs naturally in wet pine flatwoods and savannas, and along marsh edges. When not flowering, the plant is easily overlooked. But when it blooms, its charming golden flowers light up the landscape! They typically bloom in summer and fall (but have been known to bloom throughout the year) and are especially conspicuous in areas that were recently burned. A variety of small pollinators frequent the flowers for nectar and pollen.

Yellow milkwort’s showy flowers are bright yellow and born in compact, thimble-shaped clusters. They are solitary and have large, lateral sepals. Leaves are alternately arranged and have smooth margins. Upper leaves are small and lanceolate; lower leaves are large, obovate to spatulate, and appear as a basal rosette. Seeds are born in capsules.

Yellow milkwort seeds are spread almost exclusively by ants. The seeds contain elaisomes — fleshy, oil- and protein-rich structures. Ants collect the seeds and take them to their nest where they and their larva consume the elaisomes, but leave the seed intact. The seeds are then tossed from the nest into favorable germinating conditions.

Yellow milkwort (Polygala rugelli) by Mary Keim

The genus name Polygala comes from the Greek polys, meaning “many or much,” and gala, or “milk.” The genus is so-named because it was once believed that the presence of Polygala species in cow fields would result in higher milk production. Alas, this was never proven to be true! The species epithet, rugelii, refers to the German-born botanist and pharmacist, Ferdinand Rugel (1806-1879), who collected and named many plants throughout the southern Appalachian mountains, Florida and Cuba.

Yellow milkwort was historically used by Native Americans, especially Seminole Indians, as an anti-rheumatic, for heart and blood conditions, as a respiratory aid, and as a remedy for snake bites.

Family: Polygalaceae (Milkwort family)
Native range: Peninsular Florida from Lafayette to Miami-Dade County, excluding Monroe; also occurs in Nassau County
To see where natural populations of yellow milkwort have been vouchered, visit
Hardiness zone: 8B–10B
Lifespan: Annual, occasionally biennial
Growth habit: 1–3’ tall
Propagation: Seeds, root division
Garden tips: You’ll have to visit a natural area to see this little jewel as it is not commercially available in plant or seed form.

For more information on other Polygala species, see these resources: