Might be an agave americana,i'm no authority on this,so don't take my answer as gospel,just a guess.
kathi

Aloe striata hybrid? It's one I hadn't seen before, but these plants are in flower for so many months that the hummingbirds must have heaps of fortnights to visit them.

After following up on the internet with images, I see that it does look very much like the aloe straita hybrid. I think I will know for sure when the bloom opens. Thank you so much!

There are a number of them, Annie, commonly, as you see, used as parking lot plants. Not a bad way to see 'em!

Aloe striata x maculata