Landscape geraniums, often called cranesbills, are a versatile solution for garden beds. These perennial plants, distinct from the annual Pelargoniums commonly sold as “geraniums,” are valued for their hardiness and adaptability. Their ease of care and long-lasting appeal make them suitable for ground cover, borders, or general landscaping. They form dense, carpet-like plants that weave among others.
Choosing the Right Landscape Geraniums
Selecting the appropriate landscape geranium involves considering its mature size, flower color, bloom period, preferred sun exposure, and hardiness zone. Notable species include Geranium ‘Rozanne’, known for its large, violet-blue, saucer-shaped flowers with white eyes and reddish-purple veining. This hybrid blooms almost continuously from late spring into mid-fall. It grows 18 to 24 inches tall and spreads 24 to 36 inches, thriving in USDA zones 5 to 8.
Geranium macrorrhizum, or Bigroot Geranium, is adaptable to various light conditions, from partial shade to bright light. This species forms spreading clumps, serving as a groundcover and tolerating dry soils and difficult climates due to its thicker rhizomes. Its five-petaled flowers are pink, and the foliage can be aromatic.
Geranium sanguineum, or bloody cranesbill, is a low-growing, clumping form producing reddish-purple flowers from May to June, with some re-blooming into late summer. It grows 9 to 12 inches tall and spreads up to 24 inches wide, suitable for zones 3 to 9. This species is tolerant of clay soil and drought once established. Geranium endressii is another species used in landscaping, known for its spread and tolerance for light shade. Matching the plant’s characteristics to your specific garden conditions ensures a thriving display.
Site Selection and Planting
Proper site selection and soil preparation establish landscape geraniums. Most hardy geraniums prefer well-drained soil; a neutral to slightly acidic pH (5.8 to 6.5) is ideal. Incorporating organic matter, such as compost, into the soil improves drainage and provides nutrients. Some varieties thrive in full sun, while others perform well in partial shade; more sun leads to more blooms.
When planting, dig a hole twice as wide and as deep as the rootball. Place the plant so the top of the rootball is level with the soil surface. For mass plantings, space plants 18 to 24 inches apart, allowing for their mature spread. After planting, water thoroughly to establish them.
Ongoing Care for Thriving Gardens
Maintaining healthy landscape geraniums involves consistent care. While low-maintenance, they benefit from regular watering, especially during dry periods and after initial establishment. Water deeply about once a week, allowing the soil to dry out between waterings to prevent root rot. Avoid overhead watering, as this can lead to fungal diseases.
Fertilization is not a frequent requirement; hardy geraniums thrive with little to no fertilizer, as too much can promote excessive foliage at the expense of flowers. If the soil is poor, a well-balanced, time-released fertilizer can be applied in early spring. Deadheading spent blooms, especially for varieties like Geranium ‘Rozanne’, encourages continuous flowering and prevents unwanted self-seeding. For some varieties, a “Chelsea chop” (pruning back by about 50% in late May or June) promotes bushier growth and a second flush of blooms, making plants more compact and delaying flowering. Alternatively, a “Hampton Hack” involves cutting the entire plant back to about 4 inches from the ground after early summer flowering, leading to new foliage and blooms.
Integrating Geraniums into Your Landscape Design
Landscape geraniums offer diverse design possibilities due to their forms and adaptability. They excel as ground covers, forming dense mats that suppress weeds and provide continuous color. Their mounding or spreading habits also make them suitable for border edging, softening pathways and garden beds. In rock gardens, their ability to tolerate dry conditions and spread makes them a fitting choice. They can also contribute to a naturalized or cottage garden aesthetic, weaving among other plants for a cohesive look.
Hardy geraniums pair well with companion plants that share similar growing conditions. They complement roses, delphiniums, and peonies, filling in gaps and adding continuous color. Ferns and ornamental grasses offer textural contrast, their lacy fronds or slender blades complementing the geraniums’ softer foliage. Low-growing annuals like lobelia and alyssum can be planted with geraniums to create a vibrant groundcover. When selecting companions, consider complementary colors and textures to enhance the overall visual appeal.
Addressing Common Issues
While robust, landscape geraniums can encounter a few common problems. Fungal diseases like powdery mildew and rust can appear, characterized by powdery white growth or reddish-brown spots on leaves. Ensuring good air circulation and avoiding overhead watering prevents these issues. If infection occurs, remove affected plant parts and apply appropriate fungicides.
Slugs and snails can cause damage by chewing holes in leaves. Organic solutions like hand-picking, slug baits, or barriers can help manage these pests.
Leggy growth, where stems become long and sparse, results from insufficient light or irregular pruning. Pruning back the stems, especially after flowering, encourages bushier growth and a more compact form. Poor blooming can stem from too much fertilizer, insufficient sunlight (less than six hours daily), or being planted too deeply. Adjusting these factors encourages more abundant flowers.