It is best to plant Acanthus mollis and other members of the genus at a depth of 1/2 cm (1/4 inch), with a planned spacing of about 90 to 120 cm (3 to 4 feet) apart
This should be done after the last frost of spring or in the autumn.
Acanthus plants enjoy light and can be grown in full sunlight or in partly shady conditions.
The soil should be deep and well drained, ideally at a pH between 6 and 7. Acanthus plants are unlikely to survive in wet areas.
If growing the plant indoors, then it should be sown in late winter to early spring in peat pots. They require 20 to 25 days for germination at a temperature of 10 to 15 degrees Celsius (50 to 59°F).
Transfer outside in the early spring.
Caring for Acanthus in the Garden
Acanthus is a very easy plant to care for, it requires watering until flowering begins, but only when conditions become too dry. DO not overwater as plants do not like wet soils.
Acanthus Growing and Care Guide
Common Names: Bear's Breeches, Mountain thistle, Brank ursine. Common Names: Acanthus mollis, A. spinosus, A. longifolius and Acanthus hungaricus. Life Cycle: Hardy Perennial.
Height: 12 to 48 inches (30 to 120 cm). Native: Europe, Western Asia. USA: Zones 5 to 10.
Flowers: Late Spring and Summer. Flower Details: Purple, pink, white. (Beware of spikes beneath flowers) Foliage: Sharp spiky leaves. Variegated. Evergreen. Herbaceous.
Sow Outdoors: 1/4 inch (5mm). Following last frost or Autumn. Spacing 36 to 48 inches (90 to 120cm). Sow Indoors: Use Peat pots. Germination time: 3 to 4 weeks. Temperature 50 to 60°F (10 to 15 °C). Sow in late winter, transplant outdoors following the last frost.
Requirements: Full Sunlight or light shade. Soil pH 6 to 7 for best results. Good drainage. Deep soils. Water during prolonged dry spells. Propagate by root cuttings in the autumn.