Spanish bayonets...

I've had this plant, Yucca aloifolia, better known as Spanish Bayonet for about 10 years in my back alley... It's one of the first succulents that I planted. The plant was origionally a huge root with no leaves that someone was discarding and I salvaged... without knowing exactly what it was. Luckily, I planted it in the alley, against the fence and a good 8 feet from the roadway. This is lucky, because it is a dangerous plant, they don't call it bayonet for nothing. Those stiff leaves are each adorned with a single spine that can inflict a painful gouge right through a leather coat... not a plant that you want too close to where people are trying to walk.
I got the first blooms about 4 years after I planted it, and I've come to rely on it as a very dependable barometer of when spring has arrived. When these bloom, it's safe to plant outside.

Currently, it's 4 trunks, the tallest at six feet, the shortest at 4. We're in the northernmost reach of it's range, so I'm pretty sure that I won't get the 20 foot tall trunks that the plants can develop further south, but I'm hoping for 10 feet or so eventually... When it reaches it's maximum height, it'll fall over. Then the growing tip will turn to point up and it'll continue growing, with more plants growing up from the roots... Eventually, they can form dense, inpenatrable thickets.