Hardy geranium: 21 of the best hardy geraniums

By Klaudia Mihalova

Published: Tuesday, 10 May 2022 at 12:00 am

Sixty years ago Margery Fish’s book We Made a Garden was first published and it became an instant success with amateur gardeners. In it, she recounted how over the previous 20 years, she and her husband had developed their Somerset garden. She introduced her readers to plants such as astrantias, euphorbias and geraniums, which at the time were only known to small groups of plant enthusiasts. Fish was very forthright (and occasionally imperious) in expressing her opinions and her championing of hardy geraniums was unequivocal. She would later, famously, advise: ‘When in doubt, plant a geranium.’

A lot of us must have taken her advice because today geraniums are one of the most popular herbaceous perennials. At the centennial Chelsea Flower Show in 2013, visitors voted Geranium Rozanne (= ‘Gerwat’) as Plant of the Centenary.

The fondness that gardeners have for the genus is not, of course, entirely due to the bossy Mrs Fish. Geraniums are easy to grow and generally adaptable, with species that are at home in the cool comfort of woodlands while others thrive in the baking harshness of screes. In addition, the loose and relaxed character of geraniums fits well with the informal planting styles that have dominated gardens for the past 60 years.

The popularity of geraniums and the commercial success of Geranium Rozanne has spurred on nurseries and plant breeders to introduce many new cultivars and hybrids. Some are launched with the razzmatazz of a sophisticated marketing campaign while others appear quietly in the catalogues of specialist nurseries. Sorting out the wheat from the chaff only happens after we have grown a plant for a few years. Already some recent introductions, including the examples featured on these pages, are beginninSHardy geraniums (cranesbills) are easy to grow and generally adaptable, with species that are at home in the cool comfort of woodlands while others thrive in the baking harshness of screes. The loose and relaxed character of geraniums fits well with the informal planting styles that have dominated gardens for the past 60 years.

Geranium ‘Rozanne’ was found as a seedling in a Somerset garden at the end of the 1980s and produces large blue flowers with a white eye from June to October. One of its parents is thought to be a form of Geranium wallichianum, and breeders have been looking to see if this species can provide a successful sibling to Rozanne. G. wallichianum ‘Havana Blues’ has flowers of a similar blue with dark purple veins on each petal. G. ‘Rainbow’ (page 62), another G. wallichianum cultivar, has large, blue flowers with pink tones at the base of the petals. Unusually, G. wallichianum ‘Sylvia’s Surprise’ (page 61), which appeared in the Welsh garden of the eponymous Sylvia, has pink flowers. All three have the sprawling habit and long-flowering period of the species.

Breeders have also mined G. cinereum as a source of cultivars and as a parent in interesting hybrids. This European native alpine forms a neat hummock
of foliage that is covered in small flowers in late spring and early summer. Cultivars tend to have pink, deep-red or magenta flowers and all need sunshine and well-drained soil.

Most new introductions are chance seedlings but some are the result of breeding programmes. In Orkney, off the northeastern coast of Scotland, Alan Bremner has introduced many excellent geranium hybrids that have proved their value in the garden over the past 25 years. He has made thousands of cross pollinations of which few produce flowering plants and only a score have been sufficiently different to be named.

Sometimes new hybrids are marketed as improvements of existing plants. G. ‘Eureka Blue’ is a vigorous plant that develops a 1m-tall mound of large, blue flowers, much larger than its parent G. ‘Orion’ (page 63), which was itself a seedling of G. ‘Brookside’. I still grow G. ‘Brookside’. Whether you go for the latest hybrid or stick with the older examples is a matter of personal preference. Many new introductions are certainly exciting plants: Margery Fish would not be disappointed.

Most geraniums are robust and resilient plants that do not require special growing conditions other
than fertile soil and a sunny situation. G. cinereum cultivars need good drainage and thrive in raised beds. Geranium phaeum, G. maculatum and G. nodosum are woodland plants and need shade. They suffer from mildew in very dry conditions. If this happens, the best solution is to cut the foliage back to a few centimetres from the ground.

Geraniums measuring more than 30cm tall tend to flop over and become unsightly after flowering. Cutting the plant down will produce a new flush
of foliage and usually a second burst of flowers. Don’t be half-hearted about cutting back. Take a pair of shears and chop the whole plant back to about 10cm from the ground.

What’s in a name?

Plants in the related genus of Pelargonium are also popularly referred to as ‘geraniums’, which often leads to confusion. As long ago as 1901 The Gardeners’ Chronicle was bemoaning the fact that ‘the average gardener speaks of geraniums when he means pelargoniums’. The famous botanist Carl Linnaeus grouped geraniums with erodiums and pelargoniums into the single genus Geranium, but during the 19th century these were separated into distinct groups and given names that related to the shape of their seedpods. Resembling the beak of a heron, erodiums acquired their name from the Greek word for heron (erodiós) while geranium’s seeds evoke the beak of a crane (geranós).

Pelargós, the Greek word for stork, provided the name for the final group, whose seedpods suggest the stout bill of this other long-legged bird. Vernacular names of cranesbill, heronsbill and storksbill are still used to describe each group. The important difference is in the shape of the flower: geraniums have five equally sized and regularly arranged petals, whereas the flowers on pelargoniums have two upper and three lower petals.

IN BRIEF

What A genus of 420 species of hardy annuals and perennials valued for their adaptability, their ease of cultivation and their abundant flower production. Thousands of cultivars and hybrids have been bred.

Origins Geraniums are found in every continent apart from Antarctica, mainly in temperate regions. Common in woodlands and open meadows, they have also adapted to shallow soils and freezing temperatures at high altitudes. Season Mainly summer-flowering, from May to September.

Size From small alpines 10cm tall to herbaceous perennials 1.2m tall.

Conditions A few species prefer cool, shady conditions but most thrive in sunny, open situations in rich, well-drained soil.

Here are 21 of the best new cranesbill hardy geranium cultivars.

Geranium Rozanne (= ‘Gerwat’)

A mass of flowers from June to October, Geranium. Rozanne was found in Rozanne Waterer’s Somerset garden in 1989. Once established, it forms a wide, neat clump. 50cm. RHS H7, USDA 4a-8b.