Digitalis thapsi aka Spanish Foxglove

Digitalis thapsi is a perennial native to Spain and Portugal. Gardeners know it as Spanish foxglove or mullein foxglove. It belongs to the Plantaginaceae family. This plant forms clumps and keeps some leaves through winter. It is not native to Britain or Ireland. Its flowers and leafy base suit mixed garden beds.

Plants reach about 1.6–3.3 feet [0.5–1 metre] in height. Their spread ranges from 0.3–1.6 feet [0.1–0.5 metres]. Flower stems often stand around 2 feet [0.6 metres] tall. They tend to branch near the base. The basal leaves are egg-shaped, with wavy edges. Their colour ranges from mid-green to dark green. Slim, tube-shaped flowers rise above these leaves. The blooms range from pale to mid-purple. Each has a lighter throat marked with red spots. Plants take two to five years to reach full size.

This foxglove grows in a wide range of garden soils. It accepts chalk, clay, loam and sand. Acid, neutral and alkaline soils can all suit it. The best site has humus-rich soil and some shade. It also grows in full sun or full shade. Keep the soil moist, but allow excess water to drain. Avoid sites that become very wet or very dry. It can grow in exposed or sheltered spots. The RHS gives it a UK hardiness rating of H5. This covers winter lows of 5–14°F [−15 to −10°C].

Use it in flower beds, borders and informal cottage gardens. The RHS also lists courtyard, coastal and wildlife gardens as suitable settings. Its clump-forming habit suits these uses. Cut off the main flower spike when its blooms fade. This helps side shoots grow and produce more flowers. Sow seed in pots in a cold frame during late spring. Another way to raise plants is division in early spring.

Aphids may attack this plant, as may leaf and bud eelworm. Possible diseases include powdery mildew, downy mildew and leaf spot. These are risks rather than signs that every plant will suffer. All planting choices must also account for its toxicity. It is poisonous if eaten and is also toxic to pets. Do not treat any part as food. The RHS advises gloves and other protective gear when handling it.