Understanding Geraniums: More Than Meets the Eye
When discussing geranium plant varieties, it's vital to acknowledge a common point of confusion: the distinction between true geraniums (often called hardy or cranesbill geraniums) and pelargoniums (commonly known as bedding or zonal geraniums). While both are popular garden plants, they belong to different genera and have distinct characteristics. True geraniums are reliably perennial, hardy in most UK climates, and often feature deeply lobed leaves and saucer-shaped flowers, thriving in borders and woodland settings. Pelargoniums, on the other hand, are typically treated as annuals in cooler climates, valued for their showy, often brightly coloured flower trusses and distinctive leaf scents or patterns. They excel in pots, containers, and hanging baskets, adding exuberance to patios and balconies.
This article focuses primarily on the vast array of pelargoniums commonly referred to as geraniums in garden centres, as this is where the greatest variety for decorative planting is found. However, the hardy geraniums, or 'Cranesbill' varieties, offer their own unique charm and resilience for border planting, so we will touch upon them too. Understanding which type you are looking at is the first step to choosing successfully from the many geranium plant varieties available.
- Pelargoniums are commonly sold as 'geraniums' but are distinct from hardy true geraniums.
- True geraniums are perennial and hardy, ideal for borders.
- Pelargoniums are popular for containers and annual bedding, offering showier blooms.
- Variety selection depends on climate, planting location, and desired aesthetic.
The Pelargonium Spectrum: A World of Choice
Pelargoniums, the showy stars of summer displays, are broadly categorised by their growth habit and flower type, offering a remarkable range of geranium plant varieties. Among the most recognisable are the Zonal Pelargoniums (Pelargonium x hortorum). These are robust plants with distinctive, often horseshoe-shaped markings on their leaves, and they produce dense clusters of flowers in shades of red, pink, white, orange, and salmon. They are the quintessential bedding geranium, dependable performers in beds and pots.
Ivy-leaved Pelargoniums (Pelargonium hederaceum or Pelargonium peltatum) are celebrated for their trailing habit, with semi-succulent, ivy-like leaves and delicate, often single flowers. These are indispensable for hanging baskets, window boxes, and the edges of containers, creating cascades of colour. Their flowering can be prolific, provided they receive ample sun and consistent moisture.
Beyond the Basics: Speciality Geraniums
Delving deeper into pelargoniums, you encounter a fascinating array of specialised geranium plant varieties, each with unique appeal. Scented-leaf Pelargoniums (Pelargonium species and hybrids) are grown less for their flowers and more for their aromatic foliage, which releases delightful scents of rose, lemon, peppermint, or apple when touched or brushed against. These are excellent for pots near pathways or seating areas, and some, like 'Citriodorum' (lemon-scented), are surprisingly hardy.
Regal Pelargoniums (Pelargonium x domesticum), also known as Martha Washington geraniums or Show Pelargoniums, are prized for their large, flamboyant flowers with ruffled petals and often striking, dark blotches or veins. These require slightly more specialised care, often needing protection from harsh weather, but reward growers with spectacular blooms that are truly show-stopping.
The sheer diversity of pelargonium shapes, sizes, and colours makes them incredibly versatile for various garden designs and planting schemes.
Hardy Geraniums: The Perennial Workhorses
While pelargoniums dominate the annual bedding market, true geraniums, or hardy geraniums, offer enduring beauty for the perennial garden. Often referred to as Cranesbill geraniums, these plants are unfussy, drought-tolerant once established, and provide colour from late spring through to autumn. Varieties range from low-growing groundcovers like Geranium sanguineum 'Album' (blooming white) to taller, more upright types like Geranium psilostemon, known for its vibrant magenta flowers with dark centres. Their finely cut or lobed foliage adds texture, and they are excellent companions for roses and other shrubs.
Selecting the Right Geranium Varieties for Your Garden
Choosing among the myriad of geranium plant varieties available depends heavily on your specific gardening context and aesthetic goals. For vibrant, season-long colour in pots, containers, and window boxes, zonal and ivy-leaved pelargoniums are dependable choices. Consider the colour palette you wish to achieve; modern breeding offers an extensive range of hues, from soft pastels to intense scarlets and deep purples. If you're aiming for a trailing effect, ivy-leaved varieties are unmatched.
For those seeking fragrance and sensory interest, scented-leaf pelargoniums are a rewarding selection. Place them where their leaves can be brushed as you pass, releasing their delightful aromas. These also perform well in pots, allowing you to bring them closer to seating areas or pathways. Regal pelargoniums are best suited for sheltered spots or containers that can be moved to protection during adverse weather, as their large blooms can be delicate.
Plant pelargoniums in well-draining compost. Overly wet conditions, especially in cooler weather, can lead to root rot, a common pitfall for these otherwise robust plants.
Companion Planting with Geraniums
Geraniums, both pelargoniums and hardy types, integrate beautifully with other garden flora. For beds and borders, hardy geraniums complement plants like lavender, salvias, and ornamental grasses, offering a soft, textural contrast. They can also serve as excellent ground cover beneath taller shrubs. When considering companion plants for flowering displays, think about plants that share similar light and watering needs.
For instance, a pot filled with trailing ivy-leaved pelargoniums could be interspersed with upright, non-trailing plants like petunias or verbenas to create a multi-layered effect. While not a direct companion, understanding the needs of other popular bedding plants helps in creating cohesive displays. For example, growing cosmos in pots requires good drainage and sun, similar to many pelargoniums, allowing for mixed planting schemes in larger containers. Similarly, if you are planting petunia seeds, ensuring they have adequate light and warmth mirrors the requirements for germinating many pelargonium varieties.
The success of your geranium display often hinges on matching plant needs to your site conditions.
Environmental Considerations and Care
Most pelargoniums thrive in full sun and require regular watering, especially during hot spells, but they dislike waterlogged soil. Deadheading spent flowers regularly encourages more blooms, prolonging the display. Hardy geraniums, conversely, are generally more tolerant of varied conditions, with some preferring full sun and others partial shade. Their care is minimal once established, often involving a cut-back in late summer to encourage a second flush of flowers.
When comparing different geranium plant varieties, consider their mature size and spread to avoid overcrowding. Check plant labels carefully, as some varieties are more compact than others, making them ideal for smaller spaces or containers. The difference between geranium and pelargonium is fundamental to their care and suitability for different garden roles, so always verify the plant type.
Troubleshooting Common Geranium Issues
Despite their generally robust nature, geranium plant varieties can sometimes encounter problems. A common issue, particularly with pelargoniums, is leaf spot or blight, often caused by damp conditions and poor air circulation. Ensure plants have adequate space between them and avoid overhead watering, especially in the evening.
Wilting can occur due to underwatering or, paradoxically, overwatering leading to root rot. Always check the soil moisture by inserting a finger a few centimetres down; if it feels dry, water thoroughly. If the soil is already saturated and the plant is wilting, it may indicate root rot, requiring repotting into fresh, well-draining compost after removing any rotten roots.
Pest and Disease Management
Aphids are a frequent unwelcome visitor, clustering on new growth and flower buds. They can often be washed off with a strong jet of water or treated with insecticidal soap. Whitefly can also be an issue, particularly in greenhouses or on plants grown closely together. Regular inspection and prompt action are key.
Fungal diseases, such as botrytis (grey mould), can affect plants, especially in humid conditions. Removing affected parts promptly and improving air circulation can help. For hardy geraniums, issues are less common, though slugs and snails might nibble on young growth. If you're considering taking cuttings of fuchsias, for example, the timing and conditions are different from those needed for geranium propagation, highlighting the need to understand each plant's specific requirements.
Effective pest and disease control often starts with vigilant observation and correct plant care practices.
When to Take Cuttings or Sow Seeds
Many pelargonium varieties are easily propagated from cuttings taken in late summer or early autumn. This allows you to preserve desirable traits and create new plants for the following year, especially if you want to overwinter specific specimens. Select healthy, non-flowering shoots, remove lower leaves, and dip the cut end in rooting hormone before inserting into a sandy compost or perlite mix. Keep them in a warm, bright spot and they should root within a few weeks.
Hardy geraniums can also be propagated by division in spring or autumn, or by sowing seeds. True geranium seeds often benefit from a period of cold stratification. This contrasts with the care needed for other common garden plants; for example, marigold seedlings are typically planted out after the last frost, whereas overwintering geranium cuttings requires frost-free conditions.
When overwintering pelargoniums, keep them in a cool, dry, frost-free place, such as a greenhouse or cool conservatory, watering sparingly throughout winter.
Understanding the lifecycle and propagation methods for different geranium plant varieties is crucial for long-term garden success.
Comparing Geranium Plant Varieties: Key Features
When evaluating different geranium plant varieties for your garden, several key features should be considered to ensure you make the best choice for your needs. These include the plant's ultimate size, its flowering period, colour range, and its specific care requirements. For instance, if you are looking for a hardy, low-maintenance perennial for a sunny border, a Cranesbill geranium such as Geranium 'Rozanne', known for its long flowering period, or the deeply cut foliage and pink flowers of Geranium cinereum varieties would be suitable.
Conversely, if your aim is to create a spectacular display in hanging baskets or containers, you'll be looking at pelargoniums. Ivy-leaved pelargoniums offer cascading blooms and are ideal for softening the edges of pots or walls. Zonal pelargoniums provide upright, colourful displays, perfect for adding bulk and colour to mixed planters or beds. When considering a specific type, look at whether the leaves are plain, zoned, or deeply divided, and research the bloom shape – from single flowers to dense double heads.
Geraniums vs. Pelargoniums: A Direct Comparison
The fundamental difference between geraniums (hardy) and pelargoniums (often called 'geraniums') impacts their suitability for different garden roles. Hardy geraniums are typically herbaceous perennials, dying back to the ground in winter and regrowing vigorously in spring. They are generally very cold-hardy and well-suited to planting directly into garden soil, often performing well even in shadier spots. Their flowers are usually less showy than pelargoniums but are often borne in greater profusion over a longer season, and their foliage can be attractive in its own right.
Pelargoniums, on the other hand, are tender perennials, meaning they can survive mild winters but will succumb to hard frost. While they can be grown as perennials in frost-free climates or overwintered indoors, they are most commonly treated as annuals in the UK, providing vibrant summer colour. Their showy blooms and diverse forms make them popular for pots, window boxes, and summer bedding schemes, but they generally require more sun and consistent watering than their hardy counterparts. For example, while growing cosmos in pots can be straightforward, overwintering pelargoniums requires specific planning.
| Feature | Hardy Geranium (Cranesbill) | Pelargonium (Bedding/Zonal Geranium) |
|---|---|---|
| Plant Type | Perennial | Tender Perennial (often grown as Annual) |
| Hardiness | High (UK hardy) | Low (frost sensitive) |
| Primary Use | Borders, ground cover, woodland edge | Pots, containers, window boxes, bedding |
| Flower Type | Often single, saucer-shaped, borne in clusters | Showy trusses, single or double blooms |
| Leaf Characteristics | Lobed, deeply cut, often aromatic foliage | Often zoned, rounded, sometimes scented or ivy-like |
| Watering Needs | Drought tolerant once established | Regular, dislikes waterlogging |
| Sunlight Preference | Variable (sun to partial shade) | Full sun for best flowering |
Choosing Based on Colour and Form
The visual appeal of geranium plant varieties is vast. Hardy geraniums offer shades of blue, pink, purple, and white, often with striking centres or veins, and their foliage adds texture. Pelargoniums, however, present a much bolder spectrum, with vibrant reds, oranges, scarlets, corals, and deep burgundies alongside more traditional pinks and whites. Some varieties have bi-coloured flowers or distinct patterns within the petals.
When selecting, consider the form. Do you want a compact, mounding plant (zonal pelargoniums)? A cascading trailer (ivy-leaved pelargoniums)? A spreading groundcover (some hardy geraniums)? Or a stately, upright plant for the back of a border (taller hardy geraniums)? Matching the plant's natural habit to the intended location is paramount for a successful display.