(120 days) Open-pollinated. Wayne Schrader and Keith Mayberry of California Cooperative Extension made this delicious vegetable accessible to northern gardeners by developing Imperial Star in 1991. “We have had great luck here in NE Washington State Zone 5’s cool dry season. We always get at least 6–8 chokes per plant, and have gotten up to 13 each from several plants! They may not get as big as those California artichokes, but are a lot more tender. We eat the stems!” said Dodie Bowser of Fruitland, Wash. In more northern zones, most plants will bear 2–4 fruits, producing in the cooler fall weather that they prefer to summer’s full heat. Left to bloom, the chokes open into massive otherworldly blue flowers that dry well. Plants (both seedlings and mature) can tolerate light frosts but not hard ones. PVP expired. Caution: May not ripen in northernmost areas.①
3608 Imperial Star - Organic
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Days to maturity are from date of transplanting, not seeding.
Culture: Artichoke is a biennial, and in the north the young plant must be tricked into thinking it has already gone through a season of growth and a winter, a process called vernalization. Start indoors in mid-February and grow on at warm temperatures (at least 60°) avoiding direct hot sun or overwatering (misting is preferred). Transfer after 6 weeks to a cold frame when outdoor temperatures stay above 25°. Keep as cool as possible over the next 6 weeks without going below 25°. Then, set out about 3' apart, feed heavily and give lots of moisture and space (10 sq ft per plant). IRT plastic mulch and/or row covers can be helpful to hasten maturity.