Geraniums, celebrated for their vivid blooms and diverse foliage, are a cherished addition to gardens and homes. These popular plants bring cheerful color to outdoor spaces, adorning window boxes, hanging baskets, and garden beds. Their straightforward care makes them a favored choice for gardeners seeking continuous floral displays.
Understanding Your Geranium
The plant commonly called “geranium” is actually a Pelargonium, distinct from true Geraniums. Both belong to the Geraniaceae family. True Geraniums (cranesbills) are hardy perennials with symmetrical flowers, often used as groundcovers. Popular “geraniums” (Pelargoniums) originate from South Africa and are typically grown as annuals in temperate climates due to frost sensitivity.
Pelargoniums include many species and cultivars, known for showy, often bicolored flowers with two larger upper petals and three smaller lower petals. Their varied foliage can be rounded, hand-shaped, or ivy-like, some semi-succulent. Many varieties feature distinct leaf patterns or emit aromatic scents. Valued for their long blooming period from spring through fall, they provide continuous color in containers and garden beds.
Essential Geranium Care
Sunlight Needs
Geraniums need ample sunlight for prolific blooming, performing best in full sun (at least six hours daily). In intense heat, partial afternoon shade prevents leaf scorch and maintains flower vibrancy. Insufficient light leads to leggy growth and reduced flower production.
Watering Practices
Proper watering is important for geranium health, as both overwatering and underwatering can cause issues. Water thoroughly when the top inch or two of soil feels dry to the touch. Allowing the soil to dry slightly between waterings prevents root rot, which is a common problem for these plants. Container-grown geraniums typically require more frequent watering than those planted in the ground due to faster moisture evaporation. Water directly onto the soil to avoid wetting the foliage, which can spread diseases.
Ideal Soil Mix
Geraniums prefer well-draining soil that prevents water accumulation around roots. A quality potting mix for containers often includes perlite, vermiculite, or coarse sand for drainage and aeration. A slightly alkaline to neutral soil pH (6.0-6.5) is preferred for optimal nutrient absorption. Avoid heavy, compacted soils to ensure healthy root development and prevent waterlogging.
Feeding Your Geranium
Regular feeding supports robust growth and continuous flowering throughout the growing season (May through early autumn). Apply a balanced liquid fertilizer (e.g., 10-10-10 or 20-20-20 NPK) every two to four weeks. Once flowers form, switch to a higher phosphorus fertilizer (e.g., 15-30-15) for more blooms. Over-fertilization, especially with high nitrogen, can cause excessive foliage growth or root burn; always follow product instructions.
Temperature and Airflow
Geraniums prefer warm temperatures (70-85°F day, 55-65°F night) and are sensitive to frost, though they tolerate 45°F with slowed growth. Good air circulation prevents fungal diseases, especially in humidity. Crowded plants trap moisture, increasing botrytis or mildew risk.
Pruning and Propagating Geraniums
Regular pruning maintains plant shape, encourages bushier growth, and promotes continuous blooms. Deadheading (removing spent flowers) prevents seed production, redirecting energy to new flower development. Snap or cut the flower stem below its node. Pruning leggy stems rejuvenates the plant, creating a more compact form.
Propagating geraniums from stem cuttings is a simple way to create new plants. Select healthy, non-flowering stems 3-6 inches long, cutting just below a leaf node. Remove lower leaves to expose at least two nodes. Insert cuttings about 1 inch deep into a well-draining rooting medium (e.g., coarse sand, perlite, or soilless mix). Indirect light and consistent moisture encourage rooting within three to four weeks.
Common Geranium Challenges and Winter Care
Geraniums face challenges from pests and environmental stressors, often seen as foliage changes. Yellowing leaves can indicate overwatering, underwatering, nutrient deficiency, or insufficient light. Pests like whiteflies, aphids, and spider mites feed on plant sap. Fungal diseases such as pelargonium rust or botrytis blight occur in humid conditions or with poor air circulation. Addressing these issues early through proper watering, hygiene, and basic treatments like insecticidal soap maintains plant health.
In colder climates, geraniums need winter protection as they don’t survive freezing temperatures outdoors. One method is bringing potted plants indoors before frost to a bright, cool location (50-60°F). Reduce watering significantly during dormancy, only watering when leaves droop or soil is dry. Another option is taking stem cuttings in late summer/early fall, rooting them indoors for new spring plants. Alternatively, store dormant plants bare-root: dig them up before frost, shake off soil, and hang upside down in a cool, dark, frost-free area.