Something to always keep in mind with scented geraniums is that the scent description is just one persons opinion. I often wondered where some of the names come from. (The scents don't always seem to match up with the given name.)
Obviously, scented geraniums are a diverse group, so it's not surprising that their uses as diverse as well. Here are some suggestions:
Plant three of the smaller varieties in ceramic pots on a windowsill.
Fill a large clay pot with a specimen plant of Lemon Rose on the patio.
Combine them with flowers in a whiskey barrel.
Tuck a mid-sized Peppermint into a shady nook in the garden.
Plant a row of pruned Lemon Crispum as a border.
Place a matched pair of standards or topiaries at the front door.
Use them as backdrops or foundation plantings.
Pina Colada and Prostrate Rose make wonderful hanging basket varieites.
What pests commonly attack geraniums?
Some common geranium pests include the following:
Geranium aphids: These tiny, soft-bodied, pear-shaped insects suck plant juices and can spread viral diseases. They can be controlled by knocking them off the plants with a strong stream of water, an application of insecticidal soap (pay special attention to treating the undersides of leaves), spraying with horticultural oil, and releasing beneficial insects, such as parasitic wasps, ladybugs, green lacewings, and aphid midges.
Caterpillars: Several species of caterpillars chew geranium leaves. Caterpillars can be handpicked and destroyed or they can be controlled with an application of Bt (Bacillus thuringeinsis) which kills caterpillars, but does not harm beneficial insects. Cultivating the soil in winter will kill overwintering pupae. Attracting or releasing beneficial insects such as ladybugs and parasitic wasps will also help to control caterpillars.
Other pests: Common garden pests, such as mealybugs, whiteflies, and spider mites, can easily be controlled by knocking them off the plants using a strong spray of water, watering plants well during dry spells, and attracting or releasing beneficial insects. More severe infestations can be treated by applying insecticidal soap or neem.
I also use a homemade combination of 1 Tbs. lemon scented dish soap, 1 Tbs. oil soap, and 1 Tbs. baby shampoo mixed in a 1 Qt. sprayer bottle filled with water.