What do I need to do for my plants to bloom? I see many of these plants in my area already blooming, but mine show no signs that this is going to happen.

Did it get enough water?
Mine haven't bloomed yet either, but we are at 6500 ft elevation so ours bloom later.

If others in your area are blooming, its a problem with your plant. Is it getting enough sun? Enough water? Did it bloom last year?

On top o've everything else.
I believe !!!
They need to be several years old, before they bloom.
😎😎😎

Can you post a photo of your Red Yucca (Hesperaloe parviflora)

How long have your plants been in the ground? My first thought was it might possibly be a lighting or water issue but I don't really know. The database shows bloom times of, Late Spring or Early Summer, Summer, Late Summer or Early Fall so perhaps yours are just a bit late budding out this year due to cultural conditions?

Red Yucca, Hesperaloe parviflora, isn't really a Yucca, its an Agave. They only need to be a couple years old to bloom but do require a lot of sun.