Tridens flavus

Common Names

Tall Redtop, Purpletop, Redtop, Purpletop Tridens, Redtop Tridens, Purple Top Grass, Grease Grass

Summary

Tridens flavus, commonly called Purpletop, is a native perennial bunchgrass of the Poaceae family that forms a tall clump about 60–180 cm tall with a 30–60 cm spread, featuring long leaves 25–70 cm long and a pyramid-shaped open panicle bearing purple spikelets; seeds are oily, earning the nickname Grease Grass, with bloom from August through November; preferring full sun to part shade, it grows in dry to moist, well-drained soils and can be propagated by seed; it is valued for erosion control, habitat restoration, and native plantings, and provides wildlife value by supplying seeds for birds and serving as a larval host for several skipper butterflies; mass plantings create a striking purple display, while young plants should be protected from browsers.

Lifecycle

Perennial

Height

3-5 feet

Spread

12-24 inches

Hardiness Zones

Zones 4a-10b

Sunlight Requirements

Ideally Full Sun; tolerates Partial Sun to Partial Shade; does not tolerate Full Shade.

Soil Type

Well-drained soil from sandy to clay loams; tolerates dry to moist conditions; optimal soil texture: various.

Soil Drainage

Well-drained soil

Soil pH

6.5

Bloom Color

Purple

Bloom Time

Fall (late summer to fall)

Foliage Color

Green

Fall Foliage Color

Brown, Dark purple, Purple, Reddish-purple, No autumn foliage color

Leaf Lifecycle

Deciduous

Growth Rate

Moderate growth rate; reaches full size in about 2–3 years; doubles in size.

Seasons of Interest

Summer and Fall

Propagation Methods

Seeds, Division

Attracts Wildlife

Bees, Butterflies, Other pollinators, Birds