Purple Hyacinth Bean (Lab Lab) - UK, Scotland too cold?

[Susan BBPM]

I tried growing Purple Hyachinth bean - mainly as an ornamental. I've read they are extremely fast growing vines.

I'm in Scotland where we have a late May last frost date.

I started my first batch indoor in late April and planted them out in mid May (forecast was showing 10 degree C minimum night time temps for the whole of May). We had a cold spell in early june (a few nights at 7 degrees) and my hyacinth beans sulked.

I bought some more seeds and started a new batch in early June. They too started out well but as soon as I put them in the ground they sulked.
I'm now into mid July and I have 20 or so hyacinth bean plants that look healthy enough but haven't grown beyond the first 2 true leaves. Temperatures are now nice and warm - haven't dipped below 10 degrees for weeks now. Some are in the ground, some in containers with good quality compost.
Any ideas what might be wrong? Is Scotland just too cold?

 

[Chuck]

It's probably a little too cold for them now. The best plant growth temperature for them is between 70F (21C) and 80F (26C) and soil temperatures at the root zone no less than 65F (18C).

 

[Susan BBPM]

Cheers. We're now into August and they've grown about 2 inches!!
I guess I should have realized there's a reason why no one grows them around here - I thought I was being smart being the first to find them LOL