Delosperma sphalmanthoides is like a terrestrial sea anemone. Very unique amongst the genus and very dense growing. Plants have survived in our rock garden taking -7F. One of the first South African species to bloom every spring and then blooming continuosly off and on throughtout summer. Mats can reach 16' across but are more common about half that size.
Plants are shipped in pots.
I do not guarantee these in a zone 5/6 because everyones growing conditions are different but this would be a good trial plant to grow in your cold outdoor garden. Try to plant outdoor 90 days before 1st hard freeze.