The geranium might as well be called "old reliable." It's one of the most popular annuals around. In fact, you can pretty much plant it anywhere, but its ability to withstand wind and rain, combined with an aversion to temperatures above 90 degrees Fahrenheit (32.2 degrees Celsius), make it a perfect fit for gardens of the Northeast.
There are somewhere around 250 different species of geraniums in the world. Within those 250 species, there are more than 10,000 cultivars. How's that for variety? All geraniums fit into one of four basic types. There are common or zonal geraniums, ivy geraniums, scented-leaf geraniums, and show, regal or Martha Washington geraniums [source: UVM].
The focus of this page will be on common or zonal geraniums since they're the most popular type used in gardens and home landscaping. With their large flower heads and wide variety of colors, it comes as no surprise that they're so popular. Geraniums can bloom in every flower color except blue and yellow. Some even have leaves with bright edges of color such as burgundy or coral. Fittingly, they're called "fancy leaved geraniums."
When planting geraniums in your home garden you should keep the following things in mind. Geraniums generally need six to eight hours of direct sunlight throughout the day. This is important because they won't bloom as abundantly without it. Growth can also be damaged by an early frost so make sure to wait until that danger has passed. Late May is generally a safe bet for planting [source: URI].
Geraniums are available as rooted cuttings or seedlings in plastic trays. They should be planted at approximately the same depth they were growing in their pot or tray. If you plant them too deeply, they could be killed by stem rot. Depending on the amount of rainfall your garden soaks up, geraniums should be watered at least once a week. The key is to allow the soil to dry in between waterings. One way to check is to stick your finger into the soil. If it's dry two inches (5 centimeters) down, it's time to water again [source: Flower Gardening]. Make sure they're planted in a rich, well draining soil. Also, be careful not to soak the leaves of the flower. If it's unavoidable, you should water them early in the morning so they have plenty of time to dry before nightfall.
If you're looking for a low maintenance flower to brighten up your garden, you can't go wrong with geraniums.