If you’ve never grown geraniums, this is the year to do it. The National Garden Bureau has proclaimed 2012 as the Year of the Geranium.
A true geranium is a cranesbill, a hardy perennial. The bedding plant most gardeners put in containers every summer isn’t a true geranium; it’s a pelargonium. Beyond the botany lesson, there are four basic types of geraniums.
The Common or Zonal (Pelargonium x hortorum) is the classic bedding plant that comes to mind when someone says geranium.
Regal and Angel (Pelargonium domesticum) are bushy plants with large blossoms that tend to be spring blooming.
Scented-leaf (Pelargonium domesticum) are coveted heirloom plants, grown today for their pleasing fragrance and delicate flowers.
Ivy-Leaf (Pelargonium peltatum) flower abundantly and are popular for hanging baskets and containers.
Source: ngb.org