Rose of Sharon/ Hibiscus, Rose of Sharon is the only species I know of that can withstand the Utah cold. I have seen another species here with larger blooms, but I haven't found it's name. Large bush, lots of flowers, needs full sun.
Rose of Sharon is a variety of hibiscus, which is native to Indian subcontinent and other Asian countries. Planting Rose of Sharon is possible in variety of zones as it is adaptable to multiple climates.
Rose Of Sharon Pruning – How And When To Prune Rose Of Sharon
How and when to prune.The rose of Sharon shrub flowers on growth from the current year, allowing optimum opportunities for when to prune rose of Sharon. Pruning rose of Sharon shrub may be necessary at times and this article can help.