Don't believe everything you read. Plants are as individual as people, and maybe some do die out and drop seed. But if the conditions are right, the winters not too cold, d. capillaris will live as long as it wants to. Books are usually repititious about some "facts". I have rocked the boat by showing the plants don't read. And they will live as long as they are supposed to. In Peter's first edition of "Savage Garden", he stated VFT's only live two or three decades. THAT is also untrue. His later editions have changed since then since he was called on MANY mistakes in the book. Recent editions , however, are more accurate as changes were made. As far as the plants are concerned, give THEM a chance to show you what they can do, and use your instincts, some book learning, and a heckuva lot of questions. You just might be suprised. Many times----pleasantly!