David, I agree with you. For pure white, she is probably the best. Any problems with clematis wilt? I have MB and one bought under the name Mm le Coultre, that is arguably the same. They wilt every year. Start again, but will bring me a heart attack. IMO, too much cl. lanuginosa in her genes.

christopher lloyd opines that madame lecoultre was maries married name

I have a "Toki" clematis which is also a stunning white and huge 8 inch flowers.