What is Geranium Ground Cover?
Geranium ground cover refers to specific varieties of geraniums, often known as hardy geraniums or 'cranesbills', that are cultivated for their spreading, mat-forming habits. Unlike bedding geraniums (Pelargoniums) which are typically grown in pots or borders for their showy, upright blooms, ground cover geraniums naturally spread outwards, creating a dense carpet of foliage and flowers. They are prized for their ability to suppress weeds, stabilise soil on slopes, and provide continuous colour and texture throughout the growing season with minimal fuss.
- Spreading geranium varieties naturally cover garden spaces.
- Ideal for suppressing weeds and stabilising soil.
- Offer continuous colour and texture.
- Distinct from upright bedding geraniums (Pelargoniums).
The appeal of using geraniums as ground cover lies in their resilience and adaptability. Many varieties are exceptionally hardy, tolerating a range of conditions from full sun to partial shade, and are generally unfussy about soil type, provided it is not waterlogged. This makes them a dependable choice for gardeners seeking effective, attractive, and low-effort planting solutions for banks, borders, woodland edges, and between paving stones. Their diverse foliage shapes and a spectrum of flower colours add significant horticultural value.
It's important to distinguish between true geraniums (herbaceous perennials) and the more commonly known bedding geraniums, which are technically Pelargoniums. While both are popular garden plants, their growth habits and primary uses differ significantly. Bedding geraniums are often treated as annuals, bred for bold, singular blooms and a more upright structure, whereas hardy geraniums are long-lived perennials that spread to fill areas, often with smaller, more delicate, yet numerous flowers.
Why Choose Geraniums for Ground Cover?
The decision to use geranium ground cover is often driven by a combination of practical benefits and aesthetic appeal. These plants offer a robust solution for gardeners looking to achieve a lush, well-maintained look without constant intervention. Their primary advantage is their vigorous, spreading growth habit, which effectively chokes out weeds by outcompeting them for light, water, and nutrients. This significantly reduces the need for manual weeding, saving considerable time and effort over the long term.
Beyond weed suppression, geranium ground cover plays a vital role in soil health and garden structure. Their dense root systems help to bind the soil, making them particularly useful for preventing erosion on slopes or embankments. The foliage also acts as a protective mulch, retaining soil moisture and moderating soil temperature, which benefits other plants in the vicinity and helps to maintain a healthier microclimate. This makes them an excellent choice for naturalising difficult areas of the garden that might otherwise be bare or prone to degradation.
The key advantage of hardy geraniums as ground cover is their blend of effortless beauty and ecological benefit.
Aesthetically, geranium ground cover brings continuous visual interest. Many varieties produce masses of delicate, often star-shaped flowers throughout the summer months, ranging in colour from soft pinks and blues to deep purples and whites. The foliage itself is often attractive, with deeply lobed or palmate leaves that can provide texture and colour even when the plants are not in bloom. Some varieties even offer autumnal colouration, extending their visual contribution into the cooler months. This makes them a versatile component in mixed borders, rock gardens, or as a more naturalistic planting scheme.
Choose varieties suited to your light conditions: look for Geranium 'Rozanne' for sunnier spots or Geranium macrorrhizum for shadier areas to ensure optimal flowering and growth.
Selecting the Right Geranium Ground Cover
When selecting geranium ground cover, consider the specific conditions of the area you wish to plant. While many geraniums are adaptable, their performance and appearance can vary significantly. Key factors to evaluate include the amount of sunlight the area receives, the soil drainage, and the desired height and spread of the plant. Understanding the growth habits of different species and cultivars will ensure you choose plants that thrive and fulfil their ground-covering potential effectively.
Popular Geranium Ground Cover Varieties
Several species and cultivars stand out for their suitability as ground cover:
- Geranium macrorrhizum (Bigroot Geranium): Known for its highly aromatic foliage and excellent drought tolerance once established. It forms dense mats and is particularly good for shady to semi-shady conditions. Varieties like 'Ingwersen's Variety' offer lovely pale pink flowers.
- Geranium x cantabrigiense (Cambridge Geranium): Forms a low, spreading carpet of finely divided, aromatic leaves. It has pink flowers and is quite hardy, performing well in sun or partial shade. 'Biokovo' and 'Stark's Variety' are popular cultivars.
- Geranium sanguineum (Bloody Cranesbill): Features deeply cut, often purplish-red foliage in autumn and bright magenta-pink flowers. It's a more vigorous spreader, excellent for sunny, well-drained sites, and tolerates drier conditions. 'Striatum' is a pale pink, veined form.
- Geranium 'Rozanne': A celebrated, widely available hybrid known for its exceptionally long flowering period. It produces large, violet-blue flowers with white centres from late spring until the first frost, thriving in sun to partial shade and becoming a substantial ground cover.
- Geranium Pylzanne 'Rozanne': This is the same plant as 'Rozanne'.
When comparing, note that some varieties, like Geranium macrorrhizum, are more tolerant of poorer soils and dry shade, whereas others, such as Geranium sanguineum, prefer sunnier, well-drained positions. For longevity of bloom, 'Rozanne' is unmatched among the common ground cover types.
Always check plant labels for specific cultivation needs, mature size, and hardiness zone compatibility. Aim to select plants that will fill the space within a reasonable timeframe, considering their typical spread per year.
Planting and Care for Geranium Ground Cover
Successfully establishing geranium ground cover involves a few fundamental steps, ensuring the plants establish quickly and mature into dense, attractive coverings. The initial planting phase is crucial for setting them up for long-term success, especially when aiming for effective weed suppression and visual coverage.
Planting Essentials
Prepare the soil by removing existing weeds and loosening the ground to a depth of at least 15-20cm. Incorporating some organic matter, such as compost, can improve soil structure and fertility, though many hardy geraniums are not overly demanding. Spacing is key; plant them at intervals that allow for their mature spread, typically 30-60cm apart depending on the variety. Closer spacing will achieve ground cover more rapidly but requires more plants initially. Water thoroughly after planting to settle the soil and reduce transplant shock. For new plantings, a mulch of organic material can help retain moisture and deter early weed growth.
Ongoing Care and Maintenance
Once established, geranium ground cover requires minimal maintenance. Regular watering is usually only necessary during prolonged dry spells, as mature plants are often quite drought-tolerant. Deadheading spent flowers is generally not essential for ground cover types, as their prolific blooming often masks fading blooms, and many are semi-evergreen or deciduous, providing foliage cover throughout much of the year. However, cutting back plants hard after their main flush of flowers can sometimes encourage a second bloom or neater appearance. Any overgrown areas can be trimmed back; cuttings from some species can even be used for propagation.
Pest and disease issues are typically rare for healthy, well-sited hardy geraniums. The main 'care' is allowing them to do their job: spread and cover. Avoid over-cultivating around them once established, as this can disturb their root systems and compact the soil, hindering their ground-covering ability. Ensure that any nearby plants are not being choked out, and prune back the geraniums if they become too vigorous in unwanted directions.
For a continuous display, consider interplanting different varieties with staggered bloom times, or mix them with other low-growing perennials that offer different textures or colours.
The ultimate success of geranium ground cover lies in choosing the right plant for the right spot and giving it the initial opportunity to establish. Once settled, these resilient plants will provide years of attractive, low-effort ground coverage, contributing significantly to a dynamic and healthy garden ecosystem.