No. 3 is giving me a headache Paul! I can't decide where it belongs, neither can I find any which look like it. There are narrow leaved agaves and yuccas, the multiple growth can happen with both if cut back but it could be another genus. There's others such as Dyckia.
I think I found a yucca which looks similar but without the filaments and it appears to have a narrow pale edge. Yucca linearifolia is close but not close enough.
I found one which is blue and has filaments, Yucca baccata var. vespertina 'Hualampai Blue' but the leaves are broader.
http://plantlust.com/plants/yu...
That could be it, I found another photo with young plants around which have narrow leaves but not the more blue form.. the filaments can give the impression of having a pale edge. The multiple growth is probably from being cut back.
http://www.yuccaagavaceae.com/...
