I've been thinking about tulip varieties lately.
The most commonly planted types of tulips are hybrids. These are the 24" iconic wide-leaved ones everyone is familiar with. I've both heard and observed in my own yard that these tulips don't bloom for more than a year or two. They're more like annuals or biennials than true perennials.
Species tulips, the varieties the hybrids are bred from, are shorter, with different growing habits and shapes. Many bloom year after year and spread to more areas. I'll have to put more research and planning into exactly what species(es) of tulips to grow, but I definitely want to try species instead of hybrids.