Common Problems with Geraniums

The garden plant commonly known as geranium (correctly called pelargonium) is relatively easy to grow. But easy to grow doesn't mean problem-free. The good news is that most problems with geraniums are easily remedied.

Common problems with geraniums can be divided by symptoms into four categories - foliage, flowers, buds, and growth. Probably the most frequent cause of problems with geraniums is over watering, but fungus, insects, and too little sunlight also can make plants fail to thrive.

Symptoms and causes of problems with geraniums:

Problems with the foliage:
Leaves have yellow edges - the plant needs fertilizer.
Leaves turn yellow - bacterial root rot, white fly pests.
Leaves are deformed - mites are pests that can cause leaf deformation.
Leaves turn red colored - possibly magnesium deficiency or temperature too cold. Geraniums don't tolerate temperatures lower than 40 F.
Yellow or pale spots on and misshaped leaves - aphids can cause these symptoms.
Leaves wilt/stem rots - fungal disease named 'leaf spot' or 'leaf rot'.
Leaves coated with white or white patches - Powdery mildew and other fungal infections.

Problems with the flowers:
No blooms - Low light levels. Geraniums perform best when they get at least 6 hours of direct sunlight every day. Excessive heat and overfeeding are also causes of failure to bloom. If the green parts are abundantly healthy but there are no buds, chances are overfeeding is causing the problem.

Problems with the buds:
No buds - overfeeding, excessive heat, too little sunlight.
Small holes in unopened buds - geranium budworm, a moth larva, causes these problems. Small pest infestations can be handled by removing affected buds and visible caterpillars by hand.
Buds dry up/drop off - over watering, high humidity.

Problems with the whole plant:
Plant becomes spindly - lack of sufficient light. These plants require at least 6 hours of direct sunlight daily.
Plant grows poorly - soil pH of 6.5 is best; poor growth occurs below pH 5.5. Growth can also be stunted in concert with yellowing foliage by lack of nitrogen. Mealybug and white fly pest infestations are possible causes of growth problems with geraniums.
Plant is leggy - excessive feeding or watering and overcrowding will cause geraniums to look leggy, as will failure to pinch back long stems.
Wilts between waterings - often a problem with plants growing in containers. Plants can grow too large for their pots. While geraniums don't like to stay damp, they also don't like to dry completely between waterings. Repot the plant in an appropriately sized pot, and this wilting problem should disappear.

General tips for avoiding problems with geraniums:
Be sure the plant gets enough sunlight and drains well. Water only when soil is fairly dry - don't keep it wet. Feed using your favorite 10-10-10 fertilizer, mixed according to instructions. Overfeeding causes as many problems as underfeeding, so follow the instructions. If your plants are contaminated with a fungal infection, don't compost the trimmed plants - dispose of them off property.

Follow these tips to success with this low maintenance and colorful plant.