Although the name sounds exotic, zonal geraniums (Pelargonium x hortorum) are the common geraniums readily found in garden centers and planted in flower beds, window boxes and patio containers across the country. Foliage of the zonal geraniums is marked by a black or dark green band, or "zone" that is easily seen around the center of each leaf. Zonal geraniums are valued for their attractive foliage and the bright blooms available in colors ranging from pastels to vivid scarlet and orange.
- Select a planting spot where the geraniums are exposed to a minimum of six to eight hours of sunlight per day. Geraniums thrive in nearly any well-drained soil, but benefit from the addition of fertilizer. Before planting geraniums in a flowerbed or container, work a balanced, dry fertilizer into the soil. Use1 tsp. of fertilizer for each geranium.
- Plant potted geraniums in a sturdy pot or basket with a drainage hole. Select a pot measuring at least 10 to 12 inches across to accommodate the plant’s growing root system. Fill the pot with a good quality commercial potting soil, which is lightweight and drains well. Avoid regular garden soil, which becomes heavy and compacted.
- Water zonal geraniums whenever the top inch of soil feels dry to the touch, usually about once every week. Don’t overwater, as soggy soil places the plant at risk of mildew and other fungal diseases. Don’t allow the soil to become bone dry, as dry soil causes the leaves of zonal geraniums to turn yellow and drop off the plant. One watering per week is usually enough for in-ground geraniums, but geraniums planted in containers or window boxes need to be watered more often during warm, dry weather. Water by letting a hose run at the base of the plant to avoid wetting the foliage.
- Feed in-ground geraniums every four to six weeks throughout spring and summer, using a water-soluble fertilizer for blooming plants. Use the same fertilizer for potted plants, but increase feedings to every week. Refer to the label on the fertilizer container for specific rates of application.
- Pinch growing tips from new geraniums if you want to create fuller, bushier plants. Although the tips can be pinched any time the plant look spindly, blooming is postponed for about a month. Remove wilted flowers throughout the season to promote continued blooming.