When mine are finished blooming I take the clippers and give them a haircut cutting off the seedpods. Some of the leaves get cut too but that doesn't matter. They will rebloom but sparsely--not with the flush of flowers they first have. I have sucessfully divided them in the spring.

Geranium macrorrhizum is generally grown as a vigorous,, evergreen groundcover, often in dry shade. Mine has never re-bloomed, but then, I don't cut it back either. I do cut back the flowering stems to tidy it up, after blooming is completed. Being a groundcover type, it spreads ever outwards. Ger. sanguineum (e.g. striatum, John Elsley, Shepherd's Warning, Ankum's Pride,etc.) is more of a clump-former, but it is usually quite vigorous and its roots spread underground to eventually claim a large territory. I find the various sanguineums have one main bloom period, and then if cut back moderately hard, will bloom sporadically until fall. I am in zone 4, so can only speak for my area. The only way to keep these two kinds of geranium from "taking over" a garden is to dig the roots out and either replant them somewhere else or compost them. There are many other types of well-behaved, clumping geraniums. These include Jolly Bee, Rozanne, Orion, Brookside, Mayflower, Rosemoor,Tanya Rendall, the cinereums such as Ballerina, etc. Other groundcover types include the cantabrigiense group (e.g. Cambridge, Biokova, St.Ola, Karmina, Westray). These spread sideways rather than upwards. Avoid these if you don't want the groundcover habit.None of the latter re-bloom, in my experience.