Barrett Wilson is a research specialist in horticulture for Longwood Gardens, Kennett Square.

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Narrow-Leaf Ironweed
by Barrett Wilson       #Hot Plants

Flowering occurs at the tips of the compact mounds. The star-like flowers attract many kinds of beneficial insects.

With its profusion of small purple flowers and tolerance of heat and drought, narrow-leaf ironweed (Vernonia lettermannii) is a standout in the late-season perennial border in USDA Zones 4 to 9. Native to dry, rocky flood plains in Arkansas and Oklahoma, narrow-leaf ironweed thrives in almost all soil types, except soggy, heavy soils. In fact, supplemental fertilizers and excessive watering are discouraged in the garden setting. 

Narrow-leaf ironweed matures to form a compact mound around 3 feet tall, with finely textured foliage reminiscent of the popular threadleaf blue star (Amsonia hubrichtii). The flowers and nectar are highly attractive to butterflies and many species of beneficial insects. The cultivar ‘Iron Butterfly’ is widely available and has a more compact habit.

Common Name: Ironweed, narrow-leaf ironweed

Botanical Name: Vernonia lettermannii

Flowers: Purple, late summer through early fall

Foliage: Narrow, finely textured

Size: 3 feet tall and wide

Exposure: Full sun

Soil: Most types, except heavy wet soils

Watering: Keep soil moist until established.

Pruning: Late spring, if more compactness is desired

In Your Landscape: Perennial borders, masses, meadows

From Pennsylvania Gardener Volume III Issue V. Photos by Barrett Wilson.


Posted: 09/06/13   RSS | Print


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