It looks like it's a good year for Clematis marmoraria this year . Some genera of NZ plants have erratic flowering years and Clematis is one . Copious flowers one year and sometimes none the next year . Not quite sure why but it maybe because it disrupts the life cycles of seed predators .
I have now realised that I should have turned the pots to keep the flowers even . Oh well . Never mind .
The plants have been grown from seed ( at Hokonui Alpines ) then shifted here 3 years ago . The live on a table , exposed to all the elements and no protection from wind , sun or frost . The potting mix is a peat and river sand mix with a topping of 30mm of small stone chips . No added feritliser .
Seed germinates best if sown fresh . Stored seed may take an additional winter to germinate . Stratification may help