They had a few available on the day we visited.
I do not believe so normally, but they do have a plantapalooza in mid April, which is a large plant sale. If you are a member, though, I believe there is a friends preview sale.
Yes you can.
Yes, the Garden Gift Shop has plants available Tuesday through Sunday from 10:00am till 4:00pm
Not sure. Not at the museum shop. Seeds yes. Plants not sure.
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