Scarlet geraniums (Pelargonium x hortorum) are known for their vivid red blooms, adding vibrant color to any garden. These popular plants are a favored choice for continuous display in garden beds, containers, and hanging baskets. Their appeal stems from their showy flowers and straightforward care.
Scarlet Geranium Care
Light
Scarlet geraniums thrive in locations that provide ample sunlight. They perform best with full sun exposure, meaning at least six to eight hours of direct sunlight daily. In exceptionally hot climates, providing some light afternoon shade can help prevent scorching of the leaves and maintain vibrant blooms. Insufficient light can lead to yellowing leaves and reduced flowering, indicating the need to relocate the plant to a brighter spot.
Watering
Scarlet geraniums prefer soil that is consistently moist but never waterlogged. Overwatering can lead to root rot and yellowing of the lower leaves, while underwatering may cause leaves to yellow at the edges. Allow the top inch or two of soil to dry out completely between waterings. Container-grown geraniums typically require more frequent watering than those planted directly in the ground, often needing water every two to three days during warm periods.
Soil
Scarlet geraniums grow best in well-draining, fertile soil. A soil pH ranging from slightly acidic to neutral, ideally between 6.0 and 7.0, supports optimal nutrient uptake for these plants. Incorporating organic matter, such as compost or peat moss, into the soil improves drainage and enriches its nutrient content. For container planting, a high-quality potting mix formulated for container plants is beneficial, ensuring both good drainage and moisture retention.
Fertilizing
Regular fertilization supports the vigorous growth and abundant flowering of scarlet geraniums during their active growing season. A balanced, water-soluble fertilizer, such as a 10-10-10 or 20-20-20 NPK formula, can be applied every two to four weeks. Once blooming begins, switching to a fertilizer with a higher phosphorus content can encourage more prolific flowering. Always dilute liquid fertilizers according to product instructions and avoid applying them to dry soil, which can harm the roots.
Temperature and Humidity
Scarlet geraniums generally prefer daytime temperatures between 65°F and 75°F (18-24°C) and nighttime temperatures from 50°F to 60°F (10-16°C). They are sensitive to frost and will not tolerate temperatures below 32°F (0°C), typically grown as annuals in colder climates. While they can endure average household humidity levels, extreme fluctuations should be avoided. Bringing plants indoors before the first autumn frost can extend their lifespan in regions with cold winters.
Planting and Growing Scarlet Geraniums
Scarlet geraniums can be established in the garden from seeds or nursery starts. For those starting from seed, sowing typically occurs 12 to 16 weeks before the last expected frost date in late winter or early spring. Seeds should be placed in moist, well-draining seed compost and kept at temperatures around 70-75°F (21-24°C) for optimal germination. Once seedlings develop a few sets of true leaves, they can be transplanted into larger pots.
Planting scarlet geraniums outdoors should only occur after all danger of frost has passed in spring, when nighttime temperatures are consistently above 55°F (13°C). They are versatile plants suitable for containers, hanging baskets, or directly in garden beds. When planting in the ground, space plants 12 to 24 inches apart to allow for proper air circulation and growth. For container planting, select pots with adequate drainage holes and consider a depth of at least 12 inches to accommodate root development.
Common Problems and Solutions
Yellowing leaves in scarlet geraniums often signal an imbalance in care, such as improper watering, nutrient deficiencies, or insufficient light. Review the specific care guidelines to address these issues. Pests like aphids or whiteflies may occasionally infest plants; early detection and appropriate insecticidal soap treatments can manage these issues.
Pruning and Maintenance
Regular pruning and deadheading are beneficial practices for maintaining the health and aesthetic appeal of scarlet geraniums. Deadheading involves removing spent or fading flowers, which encourages the plant to produce new blooms continuously. This process redirects the plant’s energy from seed production toward developing more flowers, extending the blooming season. Pinching off old flower stalks at their base or at a leaf node is an effective method.
Pinching back the growing tips of scarlet geraniums promotes a bushier, fuller plant habit by encouraging new branching. This type of pruning helps prevent leggy growth, where stems become long and sparsely foliated. Removing any yellowed or unhealthy leaves also contributes to overall plant vigor and appearance. For overwintered plants, a more substantial prune of about one-third to one-half of the plant can be done in late fall or early spring to rejuvenate growth.