Perhaps people are planting them too shallow. I planted some last year acording to package directions and they hardly grew at all but I remembered how fantastic they grew for me 30 years before. Many instructions say 2-3 inches where it should be at least 4-5 inches. I planted them very deep this year as I would clematis with cool feet and sunny tops and they are doing real good so far. I sort of rememered that there was something odd about the way I planted them years ago and it was planting them abnormally deep for the size of the corms. Frank Cooper zone 5b central Illinois