Thanks to everyone. I understand now. I was thinking buying reblooming dls would give me a longer bloom time. I have some older clumps that were given to me some years back that really put up a lot of scapes and buds but I don't think they rebloom. But they do bloom for weeks and I adore them.
One more question---I am considering buying a few new dls next year to add a bit of purple and pink. I love some of the newer ones!!! I especially love the *prisms*. Their faces are so different. Who are the best vendors?? I won't be buying the newest introductions...just some nice, pretty ones...maybe from the past 5 years or so.