Many varieties benefit from a routine shearing or cutting back of the entire plant after the major bloom flush. This will result in a refreshing of the foliage, keep the growth habit compact and will generally result in a decent rebloom as well. Easier than deadheading individual flowers and slows those that have a propensity to self-seed as well.

What exactly is a hardy geranium? Can it be left in ground/outside yr round? Do they resemble those sold as annuals?
I grow annual types indoors but they live on forever..are these the same as hardy? Even though they'd never grow outdoors in winter here in IL..Thanks, Toni

Hardy geraniums are true geraniums unlike the annual sort which are pelargoniums, botanically speaking - they are not related. They can and should be left in the ground overnight; they will disappear over winter and reappear in the spring.