Dear All, Thank you for all these interesting responses to my introduction! It is very interesting to read the very different experience on flowering time and size of Dahlia imperialis. Are there perhaps shorter and taller forms? The difference in size seems to be considerable! Are the shorter forms themselves perhaps hybrids? If Dahlia imperialis flowers in summer in Argentina, is it perhaps just the fact that the plant needs a certain minimum size to flower at all and only being able to reach this in mild winter climate that does not kill the current year's growth. (or greenhouse coultivation?) For how long does one shoot last? More than one year? Very interesting also the news about propagating tree Dahlias from stem cuttings: does this mean just pieces (sections) of stem without leaves? Or tip cuttings of the growth tips? None of you have mentioned the point whether these Dahlias set seed. Does Dahlia excelsa set seed at all? The semi-double white one? I agree with the hybridisation problem. So far my Dahlia coccinea var palmeri always is the first Dahlia to flower and the flowers are hand pollinated in between three different clones which I maintain by root division. As I collect a lot of seed also from later flowers that have flowerd simultaneously with other Dahlias, there may be a certain mix of hybrids in it but I think the majority of seed should be pure. If there is a request for guaranteed pure seed I can select this but then only in small amounts, please do not hesitate to contact me privately in that case. Does anybody grow Cosmos seemannii? good bye for now, Uli