Dalea purpurea

Common Name: Purple prairie clover

Plant Type: Herbaceous

Habitat: Dry fields, prairies, rocky areas

Light Requirements: Sun - part shade

Soil Moisture: Dry – mesic

Soil Type: Sandy, rocky, clayey.

Height: 1 to 3 ft

Bloom Time: Late July to September

Flower Colour: Purple

Seed Ripens: Fall

Germination Requirements: Scarify seeds: Hulls must be removed. Seeds typically germinate in warm soil without the need for cold stratification.

Details/Comments: Despite its name, it is not a true clover, but a legume with a long taproot that can extend to 6-1/2 feet deep and many smaller fibrous roots making it drought tolerant, it grows best in full sun where there is a minimum of 15 inches of annual precipitation,but must grow in a soil that is well drained and it fixes nitrogen in the soil. Is cold hardy to -45.6 °C (-50 °F). In good conditions, the plant can mature in 3 years, but in drier conditions, it may take up to 5 years. These plants take their time to fill in and the slow growth is probably the reason why they are not planted that often. Is one of the last plants to emerge in spring so do not assume that it has died on you. The flowers are also small so you need to plant a minimum of 4 or five plants together to make an impact, typically growing in clumps. Do not cut the stems all the way down to the ground at the end of the summer as new stems grow from their woody base in the following spring. Your plant will grow faster if you leave a few inches of stem over the winter.It can grow in clay, but it may not overwinter as it prefers well-drained soils. A review of extensive bee community surveys from sites with prairie wildflower communities revealed that D. purpurea attracts a rich and diverse native bee fauna and predatory or parasitoid insects that prey upon pest insects. Also has been used for land reclamation after strip mining and for preventing  erosion. It benefits from a prairie burn allowing soil locked seeds to germinate after which it will grow more profusely. Has been used as part of green roof plantings meant to create habitats for prairie species. Dalea purpurea has an amazing scent! Their leaves smell strongly of an orange when crushed. The fruit is a dry, hairless seed that remains in the calyx until dislodged by a strong enough wind or by critters.It occurs in a variety of prairie ecosystems. On tallgrass prairie it is associated with plants such as little bluestem (Schizachyrium scoparium), big bluestem (Andropogon gerardi), prairie Junegrass (Koeleria macrantha), prairie dropseed (Sporobolus heterolepis), lead plant (Amorpha canescens), and silky aster (Symphyotrichum sericeum). On midgrass prairie it grows alongside several grasses such as silver bluestem (Bothriochloa saccharoides), purple threeawn (Aristida purpurea), sideoats grama (Bouteloua curtipendula), and sand dropseed (Sporobolus cryptandrus). On shortgrass prairie it is associated with grasses such as blue grama (Bouteloua gracilis), hairy grama (B. hirsuta), and buffalo grass (B. dactyloides). This species may be considered an indicator of pristine prairie. The nectar and pollen of Dalea purpurea attract many bees, wasps, flies, butterflies, and skippers. Several plasterer bees (genus Colletes) are specialist pollinators of Dalea species, and other insects eat the seeds and leaves. It is a larval host to the Southern Dogface (Zerene cesonia), Dogface Sulphur (Colias cesonia) and Reakirt's Blue (Hemiargus isola) butterflies.

Botanical Name (Alt): Petalostemon purpureum

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