Sunday, May 5, 2013

Cardoons self seeding...and, are these invasive?

In a previous post about volunteer sprouts, I misidentified what I thought were squash seedlings.  I was a bit surprised to see squash so early, and sure enough they turned out to not be squash, but cardoons!

Cardoons are the closest relation to the artichoke, another member of the same genus, also in the Aster family.  The plants look nearly identical to their better known relative, as do the buds and flowers.  Cardoons and artichoke plants and flowers, look like scaled-up versions of another well-known aster family member, the thistle.  Cardoons are harvested for the leaf stems, whereas artichokes are harvested for the flower buds.  This summer I will try to cook a bud, and I'm hoping that the flower stem will at least taste like an artichoke stem.

To the left is an earlier photo of the initial sprouts.  The cotyledons do indeed look like squash.  But, after a few weeks, we see the familiar silvery green leaves of a cardoon. Below is the same large cluster of seedlings, but now some are showing their true leaves.

I have heard that cardoons are an invasive species, but my belief was that may be so in the Mediterranean where they are from, but not here, where it takes effort to grow them.  Not all will overwinter.  But, now it appears that even if a fraction survive the winter, they are indeed invasive.  For small urban gardens, just keep the seedlings in check, and all will be fine, but just don't release the seeds into the wild.  Now I realize that I added our saved cardoon seeds to a mix that we used  for seed bombs in one of my gardening classes last Fall, so if we eventually see a Brooklyn vacant lot taken over by's the blame.  But, I'd take a lot full of cardoons over Japanese Knotweed...

These are the large seed heads that eventually were scattered around last Fall, many of which are sprouting now.  Below is one seed head that I harvested and now have as a home decoration.  One obvious way to prevent these from spreading, is to harvest (and dry) the buds, or harvest all seed heads before they open and spread.  The plants are huge so the number of flowers in a smaller urban garden will always be finite.

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