Geraniums are among the most popular plants in UK gardens, admired for their long lasting blooms, attractive foliage and ease of care. They brighten borders, containers and window boxes throughout the summer, providing a reliable display that appeals to both beginner gardeners and experienced horticulturists. However, a common source of confusion is whether geraniums are perennial plants or whether they must be treated as annuals that need replanting each year. The answer depends largely on the type of geranium you are referring to, as the term is used to describe two different groups of plants.
The two types of geraniums
When gardeners talk about geraniums they may be referring to either true hardy geraniums, also known as cranesbills, or to pelargoniums, which are tender bedding plants often sold simply as geraniums. True hardy geraniums are perennial plants that come back year after year, forming clumps that spread slowly and provide flowers from late spring to autumn. Pelargoniums, on the other hand, originate from warmer climates and cannot survive frost, meaning they are usually treated as annuals in the UK. This distinction is the key to understanding whether geraniums are perennial.
Hardy geraniums as perennials
Hardy geraniums, the true geraniums, are undoubtedly perennial. They are well suited to the UK climate and can survive winter outdoors with little protection. Once established they return each year, often larger and more vigorous, providing long term structure and colour to borders. Hardy geraniums come in many varieties, with different flower colours, heights and growth habits. Some spread to form ground cover, while others remain in neat clumps suitable for edging paths. They are low maintenance, tolerant of a wide range of soils and capable of thriving in both sun and partial shade. For gardeners seeking reliable perennials, hardy geraniums are an excellent choice.
Pelargoniums as tender plants
Pelargoniums are often what people mean when they refer to geraniums, especially in the context of summer bedding and container planting. These plants produce vibrant clusters of flowers in red, pink, white, purple and bi colour varieties, making them popular for window boxes, hanging baskets and pots. While they are technically perennial in their native habitats of South Africa, they cannot survive UK winters outdoors. Frost will quickly kill pelargoniums, so they are usually grown as annuals, replanted each spring. However, with protection they can be overwintered indoors and grown for several years, effectively behaving as perennials in a managed environment.
Overwintering pelargoniums
Gardeners who do not wish to buy new pelargoniums each year can overwinter them with some effort. Before the first frosts, plants can be lifted from outdoor containers, trimmed back and brought indoors. A cool but frost free environment such as a greenhouse, conservatory or windowsill provides the best conditions. During winter, pelargoniums need less water and no feeding, as growth slows significantly. In spring, they can be pruned, repotted and gradually reintroduced to outdoor conditions once frost risk has passed. In this way, pelargoniums can be kept for several years, effectively making them perennial plants under human care, though not naturally hardy in the UK climate.
Why the confusion exists
The confusion over geraniums being perennial arises from the interchangeable use of the word. Garden centres, catalogues and casual conversations often use the term geranium for both hardy geraniums and pelargoniums. Without clarifying which type is being discussed, it is easy to assume all geraniums behave the same way. In truth, hardy geraniums are reliable perennials, while pelargoniums are tender perennials that are often grown as annuals in colder regions. Understanding this distinction helps gardeners plan their planting and avoid disappointment when plants do not return after winter.
Hardy geranium varieties
There are hundreds of hardy geranium species and cultivars, each offering unique qualities. Geranium ‘Rozanne’ is a particularly popular variety, known for its long flowering season from early summer until the first frosts. Its violet blue flowers with white centres are a favourite in many gardens. Geranium sanguineum, also called bloody cranesbill, is another hardy type with magenta blooms and finely cut foliage. Geranium phaeum, or mourning widow, provides early flowers in deep purple shades and thrives in partial shade. These varieties illustrate the diversity of hardy geraniums and their adaptability to different garden conditions.
Pelargonium types
Within pelargoniums there are also several groups with distinct characteristics. Zonal pelargoniums are the most common, featuring rounded leaves often with darker markings and clusters of brightly coloured flowers. Ivy leaf pelargoniums have trailing habits suited to hanging baskets. Regal pelargoniums produce large, showy flowers and are often grown indoors. Scented leaf pelargoniums, valued for their aromatic foliage, can release scents of rose, lemon, mint or spice when touched. Although tender, all these pelargoniums can provide perennial enjoyment with proper overwintering care.
Growing conditions for hardy geraniums
Hardy geraniums are among the easiest perennials to grow. They prefer well drained soil but tolerate a wide range of conditions, including clay and sandy soils. They grow well in sun or partial shade and many varieties thrive in woodland edges or beneath shrubs. Once established they require minimal attention, though cutting back after flowering can encourage fresh growth and a second flush of blooms. Hardy geraniums are resistant to pests and diseases, adding to their appeal as dependable perennials.
Growing conditions for pelargoniums
Pelargoniums need more specific care to thrive. They prefer sunny positions and well drained compost, making them ideal for pots and containers. Regular feeding with a high potash fertiliser encourages continuous flowering throughout summer. Deadheading spent blooms keeps plants looking tidy and encourages new flowers. Because they are sensitive to cold, pelargoniums must not be planted outside until all risk of frost has passed, usually in late May or early June in the UK. They are best treated as temporary summer bedding unless overwintered indoors.
The role of geraniums in garden design
Both hardy geraniums and pelargoniums play important roles in garden design. Hardy geraniums provide long lasting structure and ground cover in borders, filling gaps between shrubs and perennials with colour. Their foliage often forms attractive mounds that suppress weeds. Pelargoniums, with their bright colours and compact growth, are ideal for adding seasonal impact to pots, hanging baskets and patios. They are particularly valued in urban gardens and balconies where space is limited but vibrant colour is desired. By understanding which are perennial, gardeners can make better choices about where to plant them for lasting or seasonal effect.
Environmental benefits
Geraniums also contribute to wildlife in gardens. Hardy geraniums attract bees and pollinating insects with their open flowers, making them valuable additions to wildlife friendly planting schemes. Pelargoniums are less attractive to pollinators because of their flower structure, but they still provide nectar for some insects and add visual beauty to outdoor spaces. In both cases, growing geraniums helps increase biodiversity and creates a more appealing environment for people and nature alike.
Conclusion
So, are geraniums perennial plants? The answer depends on the type. Hardy geraniums, also known as cranesbills, are true perennials that survive UK winters and return year after year. Pelargoniums, often called geraniums in garden centres, are tender perennials that cannot survive frost outdoors and are usually grown as annuals. However, with overwintering indoors, pelargoniums can also be kept for several years. Understanding this distinction removes confusion and allows gardeners to enjoy the full potential of both groups. With their beauty, versatility and ease of growth, geraniums in all their forms remain favourites in gardens across the country.
