Learn the basics of geranium care, including what type of soil they like and how to overwinter them.
2009, Dorling Kindersley Limited
The geranium, zonal, is an annual flower named for the horseshoe shaped band of dark color in the leaves of most varieties. They are upright bushes covered with colorful flowers on long stems held above the plant giving a burst of color.
Brush up on geranium care tips to grow the best geraniums ever. Whether you’re growing flowering zonal geraniums, cool-season Martha Washington geraniums or old-fashioned scented geraniums, some aspects of geranium care remain the same. Review the basics to help grow healthy, flower-packed geraniums.
On the whole, geraniums are full-sun plants. They crave sunshine and do well in locations where they receive at least six hours of sun. In warmest areas of the country, provide light shade during the hottest part of the day. Martha Washington and ivy geraniums need light shade in all regions as summer temperatures soar.
Tuck geraniums into fertile, well-drained soil. In planting beds, add organic matter to improve soil drainage and fertility. In pots, choose a commercial soil-less mix specified for use in pots. Providing the right soil is probably one of the most important foundations of geranium care. Air circulation is another.
Geraniums are easily overrun with fungal and leaf spot diseases, especially during periods of prolonged wet weather. Protect plants from disease outbreaks by ensuring geraniums have adequate air flow. Choose your location carefully, though. Too little air movement can lead to diseases, but too much wind can break stems.
Geranium care includes watering and fertilizing. Water geraniums early in the day, if possible, to avoid standing water on leaves overnight, which often leads to disease. Root zone watering with drip irrigation or soaker hoses eliminates the danger of splashing water on leaves or flowers.
Bedding plant geraniums typically include zonal, Martha Washington, ivy and scented types. These geraniums have big appetites. Mix a slow-release fertilizer into beds and pots at planting time. About four weeks later, start applying a liquid bloom booster fertilizer every other week to flowering types, including zonal and ivy geraniums. For scented geraniums or fancy leaf types with colorful foliage, use a general all-purpose fertilizer starting four to six weeks after planting. Apply these fertilizers every other week for best results.
Remove spent flowers on plants to prevent fungal diseases from developing on dead blooms. Snap flower stems off at the base. If rainy weather soaks blooms and you notice fuzzy fungus starting to grow on flowers, remove any that show mold, whether or not they have opened. This protects the plant against being overrun with fungus.
Geraniums aren’t hardy in much of the United States. Overwinter plants by carrying container plants inside and placing near a bright south- or east-facing window. Or take stem cuttings and root them. To overwinter geraniums in a dormant state, dig up plants from pots or beds, and shake soil away from roots. Place geraniums in paper bags or boxes that you stash in a cool spot for winter. An unheated bedroom, basement or fruit cellar works wonderfully.
Allow plants to dry from late fall until midwinter, when you should dip the root ball into water. Let it drip dry, then return geraniums to their overwintering quarters. In spring, when all danger of frost has passed, plant geraniums outside in pots or beds.