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Growing Hardy Geraniums

Published in Organic Gardening Magazine - May 2005

Imagine a group of plants that flowers over a long period, will grow almost anywhere, provides attractive ground cover and have blooms in a variety of stunning colours.  Add to these attributes an ability to bring bees and some butterflies flocking to the garden, and even the odd bullfinch, and you have perhaps the perfect group of plants for any wildlife friendly plot.  I am always on the lookout for plants that have good wildlife value that will survive in my clay soil and one large group of plants has exceeded my expectations.  Even the fancy varieties have the natural and unspoilt charm of their native cousins.  They are the cranesbills or hardy Geraniums, and I for one wouldn’t know what to do without them.  Cranesbills are perfect plants needing only the minimum of maintenance and attention. They will also grow in dry shade – a real plus if you have trees that remove the last remaining drop of moisture from the soil beneath.  Perhaps a few varieties self seed rather too prolifically, but if this is into shady soil where little else will establish, we really can't complain!

We have a good number of native cranesbills in this country, named after their long ‘beaky’ seed pods.  The meadow cranesbill, Geranium pratense, is perhaps the most well known, and grows in the wild on dry chalky soils.  In the garden is a perfect plant in almost any soil.  The sky blue colour varies depending on the soil type, and is said to be at its most glorious blue in my home county of Oxfordshire.  However like all the Geraniums, there is a wanton tendency to cross pollinate with others in the genus, leading to a variety of colours from the palest blue to the colour of a Mediterranean sky.  What ever its final colour it is a lovely plant for a meadow or border. There are several other versatile natives.  The hedge or mountain cranesbill, Geranium pyreniacum, has dainty mauve flowers.  This plant can often be seen along roadsides in light shade and it flowers in late spring and early summer.  In the garden it will occupy difficult spaces beneath dry hedging as long as the shade is not too dense.  Geranium sanguineum is familiar to many gardeners as a ground cover or rockery plant.  Known as bloody cranesbill, it is tolerant of sunny, dry conditions and comes in a variety of colour forms as well as the dark red wild type.  Geranium phaeum or mourning widow, with its dark purple, almost black flowers is another favourite native for dry shade, and in its white version, really lights up a dark corner. 

                      wild meadow cranesbill 

Of all the natives perhaps the most striking is the wood cranesbill, Geranium sylvaticum.  In the wild this plant sometimes creates swathes of purple-blue in dappled woodland.  In the garden the larger flowered varieties of the wildflower come in blue, pink and white and are quite stunning, being up to a metre tall on sturdy stems.  Other small native species may not have the impact of those already mentioned, but the dove’s-foot cranesbill has great wildlife value, being one of the larval food plants of the tiny brown argus butterfly.  This little plant, with its hairy round leaves, is often found in lawns or as a garden weed.  Geranium robertianum or Herb Robert brings colour to the garden at any time of year.  Its attractive green leaves become suffused with crimson in cold weather, giving a splash of red to a dull corner in the winter months, and the tiny pink flowers may appear at virtually any time.

wood cranesbill

dove's-foot cranesbill

As Geraniums are found all around the world in a range of habitats, it is no wonder that it is possible to find a variety that will suit any garden situation.  The large Mediterranean species, G. palmatum, came originally from Madeira and needs a hot dry spot to thrive as it is not reliably hardy.  It is worth the effort though as in the right place it can reach well over a meter in height and the branched spike of flowers bears a profusion of bright pink blooms.  Other tall varieties include the colourful G. psilostemon which has bright magenta flowers with a dark eye, and dominates a border with its dramatic colouration.  May and June are perhaps the best months for hardy Geraniums, especially our natives.  The foliage grows quickly in the spring to produce a mound of attractive leaves and the flowers appear from mid month onwards and, depending on species, may continue well into the summer months.  If the plants begin to look a little worn in the summer, the foliage can be cut right back to produce a new flush of fresh growth.  I prefer to cut back just a few in full view to refresh the leaves, leaving other plants alone to provide cover for wildlife through the summer months.

There are so many hardy Geranium varieties and species (well over 200) that it is possible to become a little confused.  Their ability to hybridize at will also means that new varieties appear all the time in nurseries and garden centres.  If you grow a selection you will soon find that you have your own unique collection.  But in spite of its chameleon nature, the hardy Geranium has the ability to attract insects even where the plant has changed from the original species through deliberate or accidental hybridization.  The open flowers have copious amounts of pollen and are particularly good for the smaller bumblebees species and solitary bees.  Some, especially the natives, also have nectar and several butterfly species will visit the flowers.  The majority of the garden forms set seed well and these seeds are large and nutritious. All the finches seem to like them, but in particular the bullfinch is fond of the seeds of several of the species.  In my garden I can expect to see a family of bullfinches in June searching for the seeds of mourning widow, Geranium phaeum, but also several of the other species including the humble herb Robert. 

geranium and bee

You could be forgiven for thinking that plants with all these virtues would be difficult to grow, but of course they are simplicity itself.  They benefit from the occasional organic mulch and the tired foliage can be cut back in summer if you wish to provide a fresh burst of growth, but this is certainly not necessary.  Removal of the previous season’s dead leaves can be done in early March but watch out!  I have more than once found a hibernating hedgehog beneath the mound of winter foliage.

Propagation is also easy as plants can be split or grown from small rooted pieces, and seeds germinate well after a cold winter.  All in all, at least in my garden, these are perfect plants.  Colour, attractive foliage and drought tolerance together with the ability to attract bees, butterflies, bullfinches and even the occasional hedgehog!  Every wildlife garden should have some.