I have given up on getting the plants through our harsh winters, but have no problem getting them to produce two flushes of medium and small buds when grown as annuals. The trick is to start the seeds early, in January, grow them warm indoors for a while, and then subject them to limited cold by setting them out under protection in late March-early April.

See very interesting thread from 2013 below.

Here is a link that might be useful: 2013 artichoke thread

My zone says 6b but I swear it should be in 5b because we usually get down to -10 to -15 every year. I have had chokes in the ground that have come back the last 3 years. I chop the leaves off to about 6 inches (it really doesn't matter they will die to the ground) then I throw a pile of leaves or straw over them about a 1-2 ft deep and lay a tarp over them. The roots seem to survive no problem the ground here never freezes more than 3-4 inches deep.

Mentioning this because of your location in NoVA. Years ago DeBaggio's herb farm had artichoke varieties and a whole protocol for growing them. My memory is vague but I seem to recall (late 1990s) one of the owners saying they sold starter plants in late February, before the nursery had properly opened for the season, but generally after the risk of extreme cold. It seems the point was to get them flowering before hot weather because that will reduce the quality of the buds. It was so long ago I had this call I can't remember if it was before or after they moved to Centreville...in fact one of the first things I called them for. (asking whether they had artichokes) Around that time frame though, I never actually visited the Arlington location but I know I called it a couple times. In fact, now that I think about it I think the reason I _didn't_ visit was they told me I was too late to get them that year. Maybe it was something like you had to sign up in late February, you got them in late March before the nursery opened, etc. etc.

So, you might contact them to see what they are advising these days. The cardoon can definitely survive milder winters in the DC area, I've had a few in my gardens, but not the more severe ones. I think it's considered a bit hardier though.

This post was edited by davidrt28 on Thu, Nov 13, 14 at 11:26

Okay - The dye is cast; I am officially suffering from spring fever. I ordered artichoke and leeks seeds from Johnny's seeds. I will get 25 artichoke seeds, but expect I will plant only 10 plants. If I plant 20 seeds and get a 50% germination rate I will be satisfied. I am going start them under lights in my basement around January 10, 2015. I will start hardening them off around April 1 and transplant them to my raised bed in mid-April and cover as needed at night or during an unexpected cold snap. I realized that last year I did not get blooms because I transplanted them around May 3 and they did not get enough chill hours below 50 degrees. In any case Thomas Jefferson made it work at Monticello, so I should be able to make it work also.

Hey Charlie, I can't shed too much light on overwintering them, but I did get a nice harvest of several medium and small chokes this summer. And that was from only two plants. I had had so many disappointments in previous years and only one successful harvest before this summer that I only planted the last of my seeds to empty the packet. Of course that means I'll be ordering more this year, now. Anyway, you propose basically the protocol I used.

I'm going to try keeping this years plants over the winter, but beyond the freezing I tend to get voles in my garden each winter and they love the artichoke roots. So we'll see who wins the battle this year, them or me. So good luck! I have pretty much the same weather you do, it bodes well!