Hardy geraniums, commonly called cranesbills, are the stalwarts of a garden – they grow without fuss and bother, they flower reliably and without the gaudy excess of other garden premadonnas. For this reason, they are often overlooked as things of interest and beauty. However, they are lovely plants that offer an abundance of brightly coloured papery flowers carried above decorative foliage. Some are evergreen, while others have lovely autumn leaf colour. They are generally very long flowering, require little attention and are ignored by pests and diseases. Hardy geraniums range in size from ground-smothering plants that grow to 25cm (10in) high up to border beauties reaching 1.5m (5ft). As a rule, they can survive in almost any garden situation from hot, dry and sunny…to cold damp and shady. They can be planted in alpine gardens, in pots, in the middle of the border, at the front of the border or as groundcover. Hardy geraniums should not to be confused with tender bedding geraniums which are more correctly known as Pelargonium. The hardy geranium clan includes some 500 members so choosing the right one for your garden can be a daunting task. Here, we select the very best.
Mixed border geraniums
One of the best blue-flowered geraniums is G. x magnificum. The flowers are of the richest violet-blue and it will stop you in your tracks on a summer's evening as dusk falls and everything takes on an irridescence. This variety is a good geranium for a mixed border growing to 60cm (24in) where it makes a good partner for Gaura lindheimeri which bears starry white flowers that also glow in that fading light. G. x magnificum also has warmly tinted leaves in autumn. A good variety to look out for is ‘Rosemoor’. Another richly coloured geranium is 'Wargrave Pink' with its bright, salmony pink flowers. It grows vigorously, holding its own in any mixed border. It will reach 30cm high, but can spread up to a metre. A real pale delicate beauty is G. pratense 'Mrs Kendall Clarke' which bears flowers of the loveliest pearly colour, flushed with a silvery pink or lilac. It grows into a good shape, reaching 60cm (24in), and will not become too sprawling. If, on the other hand, you have lots of room and want your geraniums to roam plant . The flowers are quite small, but are a striking purple-brown against the fresh green of the leaves. This geranium will self-seed all over the place.
Front of the border
A beautiful small geranium is G. renardii which bears simple white flowers that are veined purple. However, the leaves are the real delight. They are the softest leaves to touch, coloured grey-green and beautifully scalloped shaped. It is a geranium which prefers a sunny, well-drained site and since it grows to only 25cm (10in) it is eminently suitable for a rock or alpine garden or the front of the border.
Another small geranium perfect for such a sunny spot is G. x cinereum. The leaves are a really softly textured green and the plant makes a very pretty mounding shape just 15cm (6in) high. The flowers will appear in April and keep going (if you give it a deadhead trim now and again) well into October. Perhaps the best widely available variety is 'Ballerina' bearing pale pink flowers with very distinct dark veins.
As a rule, geranium foliage is not noted for being aromatic. However, the wonderful evergreen G. macrorrhizum is the exception producing delicious, lemony aromatic leaves – which turn shades of orangey-red in autumn. It is mat-forming by nature and drought tolerant, making it an ideal groundcover geranium. A really tough and reliable plant. Good varieties include 'Album' (white), , 'Czakor' (magenta) and 'Spessart' (white).
Geraniums are generally very adaptable and forgiving plants which will tolerate most soils (unless really waterlogged) and, as a rule, cope with either sun or shade. The exceptions are the smaller species which do need sun and free-draining soil. During the growing season, feed with a balanced fertiliser, such as growmore, every month and water during prolonged dry spells. In the winter they will prefer to be kept quite dry.
Pruning off the dead flower heads will encourage further flowers later in the season. The foliage of some varieties, such as G. pratense, can look tatty by mid-summer, but they can be cut back hard with shears to encourage a further flush of fresh foliage. Give trimmed plants a thorough soaking and a boost with a high-potash fertiliser, such as tomato feed.
Geraniums are fairly trouble free although they can be attacked by vine weevil larvae, slugs and snails. Also, in dry conditions, they may suffer from powdery mildew. A good layer of mulch applied in spring will help to combat this. The mulch helps maintain the soil moisture level which will prevent the water stress that encourages the fungus.
Geranium seeds can be sown outside in containers in spring. Collecting seeds from plants in the garden is a difficult process. They have to be gathered at exactly the right time so that the seeds are ripe but before they fall. It is much easier to take cuttings in spring. These should root well given some bottom heat. Larger clumps can be divided in spring which will help them generate lots of fresh new growth and give you more plants to move around your garden or give to friends.