Oleander help?

I bought 3 -3 gallon Oleanders last year, and all bloomed their heads off all summer. I over wintered in the basement, and all look healthy but no blooms, all in full sun, temps in the 80's, have osmacote and planted in ground.

What do they need?

Thanks!
Vi

Water when dry and feed bloombooster fertilizer a few times.Mine are blooming great in half day sun.They are mostly in pots..a few in the ground.