Cynara cardunculus var. scolymus
217 days —'Imperial Star' plants are compact, upright, and reach about fifty-seven inches at maturity. The first flower head is ready to harvest in about 217 days from seeding, with up to six secondary shoots that extend the harvest period to about fifty days. The flower heads are large (four to five inches in diameter), tight, spherical in shape, a waxy or glossy bright green color, with slight purple coloration near the bottom of the flowers. Unlike most common cultivars, 'Imperial Star' is thornless.
Artichoke flowers are an excellent delicacy when boiled or steamed until tender, served hot,
and the inner petal tips and hearts dipped in melted
lemon-butter (some of my family like to dip them in mayonnaise).
In general, artichokes are an interesting and attractive perennial with huge, edible flower buds and stalks. They can be grown as an annual if you sow the seeds indoors in mid to late winter and set out after all danger of frost has passed. In many parts of the world, they are grown as tender perennials. Although they are a perennial, the plants will require winter protection if you live in a zone that experiences severe freezing. Because the plants are interesting, attractive, and come back from year to year, artichokes make a great addition to your flowerbeds. Here in Oregon, we have had 'Imperial Star' freeze, thaw, and continue growing. Most years we allow them to go dormant, remove all of the above ground foliage, and heavily mulch the crowns to protect them during their winter nap.
Another example of classical breeding, years of time, and a lot of work, 'Imperial Star' was developed by Keith S. Mayberry and Wayne L. Schrader, farm advisors for the University of California Cooperative Extension Service in Imperial and San Diego counties, respectively. They started their selection work with F4 generation artichoke seed lines obtained in 1985 from Joe Principe, USDA breeder at the USDA's research field station in Brawley, California. The seeds from the Brawley Station began in 1981 with a cross of a 'Green Globe
' selection that originated from France, with an individual plant from a thorny, Italian-type artichoke from Bari, Italy.
These seed lines formed the basis for mass crosses and selections which by the eighth generation, led to the distinctive bud characteristics, earliness, uniformity, and yield potential of the 'Imperial Star' cultivar. This open-pollinated variety is documented as being quite stable, with less than two percent of the plants exhibiting slightly flared, "pineapple bud shape," less than one percent having a slightly reddish hue, and approximately three-hundredths of one percent (3 in 10,000 plants) that produce spines on the flower heads or plants.
It was originally introduced, and PVP awarded in 1991. PVP expired in 2009. Hardy in USDA zones 8 to 10. Each packet contains one gram, which is approximately 15 to 20 seeds.
The exact origin of artichokes is unknown but they are presumed to have
originated in North Africa where they still grow wild. They have been
part of Mediterranean cuisines (Roman, Greek, etc.) since ancient times.
Even today they remain an important winter vegetable there. Thomas Jefferson grew artichokes in his gardens and documented them off and on in his garden journals from 1770 until 1825.