Aloe juvenna has been sold mislabeled for many years as either Aloe squarrosa or Aloe zanzibarica (a synonym for squarrosa.) This causes a lot of confusion, especially when you google Aloe squarrosa…and tons of pictures of Aloe juvenna come up. Some places will even have in the description that they are similar plants and hard to tell apart (usually the places selling juvenna as squarrosa.) They really aren’t.
They are both green and spotted and tend to trail or crawl along the ground as they grow (though squarrosa hangs off cliffs in habitat), but that’s really where their similarities end. I bought a real squarrosa last year that came in rough shape and went downhill fast, so I don’t have many good photos of my own to share to show the differences. There is one person on Flickr that has an excellent and well photographed Aloe collection, and they have an album of their squarrosa plant(s)…the Dave’s Garden plant file and Agaveville forum gallery also has good photos. The link for the Flickr gallery is – https://flickr.com/photos/32378995@N08/sets/72157614547415780
Aloe juvenna was one of the first Aloes I ever bought, back in 2008. Guess what it was labeled? Yep, Altman Plants was selling it as Aloe squarrosa. Now they sell it as Aloe zanzibarica, or Zanzibar Aloe. Also incorrect, thanks Altman. Anyway, I was pretty excited when I looked it up and read it was rare. Then I kept looking…and what I really had was Aloe juvenna. Ok cool, still a nice plant. Eventually it became an unruly mess of stretched out offsets…which is pretty common, these guys need a LOT of direct sun to remain compact. They will still start to crawl out of wherever they are planted as they grow, but at least they won’t be so stretched out. This is why they are also often mixed up with “Climbing Aloe”…which is an Aloiampelos, usually referring to Aloiampelos ciliaris. There are plenty of Aloes that “climb” and trail, but the easy way to tell if what you have is an Aloiampelos – they don’t have spots and they have very soft “teeth”. On Aloiampelos ciliaris, the soft teeth wrap all the way around the stem at the base of the leaf.
Aloe juvenna is native to Kenya, and Aloe squarrosa is native to Socotra. This is what the Wikipedia entry had to say about Aloe juvenna and Aloe squarrosa – “Aloe juvenna is frequently confused with Aloe squarrosa from the island of Socotra. However Aloe squarrosa has long, smooth, spotted leaves that curve backwards. These recurved leaves are kept only around the head or top of each stem, with dead leaves falling off the lower parts of the stem. It is relatively rare in cultivation. Aloe juvenna has many short, straight, compact triangular leaves, which are densely packed all along the stems. It is common in cultivation but extremely rare in habitat. Aloe juvenna is also a tetraploid, with a double set of chromosomes (28, instead of 14) and, in appearance, does not resemble any other Aloe species from the region.”