Just wanted to add that crested semps can be propagated by division like normal ones, so there is no reason to lose them. I do not know if there is a "genetic" or programmed limit to how long you can propagate them this way, but had one that lasted 3 years and used it to produce additional plants before losing them all last year (bad weather for their new location)
Also, it seems that some of the "line" types will zig-zag while others will maintain the line and end up curving in on themselves over time. By that I mean that some zig-zag flat across the ground while others will grow out and down around, almost in a spiral or corkscrew.
