On 18/06/18 11:45, Charlie Pridham wrote:
On 16/06/2018 22:24, Jeff Layman wrote:
Kniola's Black

Definitely an annual that one, depending on where the seed falls May or
June is when they germinate, seeds seem remarkable cold resistant

Good point - I hadn't thought to check whether or not it was an annual.
Even so, it seems it is hardy to Zone 7 and is not frost sensitive (See
"Physical Information" at
https://www.pfaf.org/user/Plant.aspx?LatinName=Ipomoea+purpurea), and
according to Missouri Botanic Garden it can be overwintered
(http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b754).

I wonder if I had plants which had not had time to flower last year, and
had overwintered.

--

Jeff