singleton--
The Geraniums you buy today aren't like they were in your Grandmother's day. They have been hybridized to have bigger and more flowers and the scent has gone by the wayside in favor of them. Personally I'm glad. I have many Geraniums on my patio and with both my husband's and my allergies I couldn't have them if they were scented.

If you want scent plant Allyssum around your Geraniums. It will fill in the base of the planter and spill over the side and they are very sweet scented

Great idea Oilpainter, and I just happen to have Allyssum that hasn't been planted yet!

You can also seek out the scented geraniums currently available, and tuck a few in next to the red ones. They are harder to find, and most varieties bloom only rarely, but they are fun in themselves. I've grown lemon, rose, mint, and nutmeg scenteds and did find they actually smelled as they were supposed to. There are also strawberry, apple, pine and coconut scenteds out there, and the gangly citronella-scented one sold as a mosquito plant. The different varieties have different leaf sizes, shapes and textures, and different growth patterns. Some grow upright in columns, some make tidy clumps, some sprawl, and some trail gracefully over the side of a container. The scent won't waft across the deck; it only becomes apparent when the plant is touched. The mint scenteds are particularly soft, furry and pettable, like stachys (lambs' ears) leaves.
Care is similar to the regular geraniums.