C. cardunculus. This striking perennial heirloom is grown as an ornamental artichoke but its leaf stalks and stems are edible. It grows at least 1.2m (4’) tall for a stunning Mediterranean look with large silvery-green, deeply-cut leaves and thistle-like flowers of rich, royal purple. Its flowers are highly attractive to bees and other pollinators. Thick stems, steamed and seasoned, are an old-world treat. The unopened flower buds make unusual cut flowers.
Matures in 150-210 days. (Open-pollinated seeds)
It takes some work and a lot of patience to grow artichokes from seed, but it’s worth the effort. Commercial culture is limited to warm areas in Zone 7 and above. Artichokes require good soil, regular watering and feeding, plus frost protection in winter. Before frost, cut back to 15cm (6″) tall and mulch with soil, straw, or leaves to keep the root from freezing. Uncover in April. Offshoots of these plants should be set out in the spring, so that the older plants can be replaced after a few years. Follow along with this handy How to Grow Artichokes from Seeds Guide and grow food.
Cynara cardunculus var. scolymus
We Recommend: Imperial Star (AR103). Harvesting artichokes in the first year of growth is a real benefit for growers. Imperial Star grows beautifully in an open field situation.
Season: Cool season
Exposure: Full sun
Zone: 6 (hardy in Zone 5 if you use mulch and cloche cover)
Start indoors in late winter, four to six weeks before the last frost date. Keep seedlings under bright lights.
Sow two seeds per pot, 5mm (¼”) deep. Keep moist in a warm place until seeds germinate in 10 to 21 days. Transplant seedlings into the garden 2 weeks after the last average frost date for your area. Artichokes need a cool period (250 hours — approximately 10 to 11 days) below 10°C (50°F) to induce flowering in the first year, but will not survive hard frost. Space plants 1m (3′) apart. Seeds can also be germinated between damp sheets of paper towel.
Days to Maturity
Ideal pH: 5.6-6.6. Select a sunny, sheltered location with well-draining soil. Dig in lots of compost or rotted manure and add 1/2 to 1 cup of complete organic fertilizer per plant. On the coast, with protective mulch, these plants may overwinter. Approximately two weeks before the last frost date (or if hard frost is forecast) cut the plants back to 15cm (6″) tall, and mulch well with straw, soil, leaves, or burlap, to keep the roots from freezing. Uncover after the last frost date.
In optimum conditions at least 70% of seeds will germinate. Usual seed life: 1 year.