Plant of the Week: Wild White Indigo

The High Line's planting design is inspired by the self-seeded landscape that grew up between rail tracks after the trains stopped running in the 1980s. Today, the High Line includes more than 300 species of perennials, grasses, shrubs, and trees – each chosen for their hardiness, adaptability, diversity, and seasonal variation in color and texture. Some of the species that originally grew on the High Line's rail bed are reflected in the park landscape today.

This week we share one of our gardeners' current favorites with you.

Baptisia alba, or wild white indigo, is an upright perennial that forms 2- to 3-foot-high stands, with showy flowers on charcoal-grey stems. The stems themselves sprout soon after spring bulbs are finishing and closely resemble dusty purple asparagus as they emerge. They grow quickly into a shrub with beautiful, stiff flower clusters. Happy in both moist and dry soil and hardy through Zone 5, wild white indigo is found across the eastern United States, growing along marshes, lakes, and clay hills. From its shape, it's clear to a keen observer that it's a sister plant to the lupine.

Like many heat-tolerant plants, wild white indigo has smooth, blue-green foliage, which moves beautifully in a breeze and creates a lovely, naturalistic look in borders and cottage gardens. It acts as a perfect focal point in spring and an effective filler in summer. The flowers are excellent for cutting during their 1-2 month bloom time; quickly after blooming, they are replaced by striking green seed pods that later turn black and persist throughout the winter. You'll see wild white indigo on the High Line, as well as a few other cultivars with blue, purple, and yellow flowers. Although blue is the most common in gardens, it is actually the rarest color in the genus.

Wild white indigo is poisonous to mammals, making it a smart deer-proof planting, yet it does attract insects of all stripes. Butterflies and bumblebees are some of its more charming visitors, while the Wild Indigo Weevil is a more menacing presence. The Weevil feeds on all parts of the plant – the leaves of any specimens collected in the wild should be checked for tiny holes before being introduced to a garden. Although slow to grow as a young plant, the established wild white indigo grows easily, for many years, and without much maintenance. Even better, its roots increase nitrogen levels in the soil, acting as a natural fertilizer in your garden.

The juices of many wild indigo species turn a vibrant blue on contact with the air, and have been used as a substitute for true indigo dye for centuries. The botanical name, Baptisia, comes from the Greek word bapto or baptizo, which means "to dye" or "color."

PLANTING TIP

Though accommodating of most conditions, the wild white indigo prefers full-to-partial sun and well-draining soil. Due to their slow early growth, plants sold in nurseries are usually 1-2 years old. They may appear thin at this age, but don't be deterred – they fill out beautifully once established, and spread vegetatively by rhizomes.

WHERE TO SEE THIS PLANT

On the High Line in the Gansevoort Woodlands, between Gansevoort and Little West 12th Street.

Download our May bloom list.

Our horticultural team counts on members and friends like you to help keep the High Line beautiful and thriving. Join our community of supporters who play an essential role in the High Line's most important gardening projectsbecome a member of the High Line today!

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