Purple Foxglove (Digitalis purpurea) — identification, habitat & look-alikes

Purple foxglove is a European wildflower and cottage-garden favorite that has escaped cultivation and now grows wild in more than twenty US states. Every part of the plant is poisonous, yet its leaves gave medicine the heart drug digitalis.

Appearance

Growth form: A or short-lived perennial. The first year it makes a low rosette of large, soft, hairy leaves; the second year it sends up a flowering stalk usually 3–5 ft (1–1.5 m) tall, sometimes up to about 6 ft (2 m).
Flowers: Tubular, bell-shaped flowers 1–3 in (2.5–7.5 cm) long hang from one side of a tall spike. They are usually pinkish purple, sometimes white, with dark spots inside.
Flowering time: Late spring into summer of the second year, opening from the bottom of the spike upward.
Fruit: A small capsule packed with tiny, dustlike seeds.

Look-alikes

woolly foxgloveDigitalis lanata

Woolly foxglove has smaller flowers, up to about 1 in (2.5 cm), that are pale yellow to creamy white with brownish veins and a curled-down white lower lip, plus densely woolly sepals.

Why they get mixed upBoth are tall foxglove spikes. Woolly foxglove, also called Grecian foxglove, is a prohibited noxious weed in Minnesota, so it is worth reporting rather than pulling bare-handed.

yellow foxgloveDigitalis grandiflora

Yellow foxglove has pale yellow flowers with a brown net pattern inside and comes back year after year as a long-lived perennial.

Why they get mixed upBoth are grown in gardens, and they can hybridize (the hybrid is Digitalis × fulva).

Where it lives

Typical habitats: gardens
moist meadows
roadsides
forest clearings
Range: Native to western Europe and Morocco. It is introduced in the US and has naturalized in more than twenty states and several Canadian provinces. In California it is established along the central and northern coast and in the Sierra Nevada foothills.
Preferred conditions: It quickly moves into disturbed soil such as logged woodland, roadsides, and moist meadows, and it tolerates shade and acidic soil.

Growing it

Care: Hardy in USDA zones 4–9. Grows in full sun to part shade, ideally with afternoon shade, in moist, well-drained, acidic soil rich in organic matter. Deer and rabbits usually leave it alone. Let some flowers set seed if you want plants to return, or deadhead to limit self-sowing.
Toxicity: All parts are highly toxic. Its can cause nausea, vomiting, an irregular heartbeat, and death. It is a danger to children, cats, dogs, and horses.

Name and classification

About the name: Besides the widespread typical form, three subspecies live only in small areas of northern Portugal, central Spain, and Morocco.
Varieties and forms: Many cultivars come in white, cream, pink, and apricot.

Conservation

IUCN Red List: LCLeast ConcernLow risk of extinction
Threats: Where it naturalizes it can form dense patches that crowd out native plants. In California its overall impact is rated as limited, though it can be locally persistent.

Culture and stories

Culture and stories: The genus name Digitalis comes from the Latin for finger, after flowers that look like they could slip over a fingertip.
In the 18th century the English physician William Withering showed that foxglove could treat dropsy (fluid buildup from heart failure), launching its use as a heart medicine.