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How to grow hardy geraniums

How to grow hardy geraniums

Published: Thursday, 16 September, 2021 at 9:44 am
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All you need to know about growing, propagating and caring for hardy geraniums, in our expert Grow Guide.

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Hardy geraniums, commonly known as cranesbill geraniums, cranesbills or 'true geraniums', are reliable, long-flowering, easy-to-grow plants. Within the genus there are tiny alpine geraniums and substantial border geraniums, flowering in a wide variety of colours. The 'weed' herb Robert is a cranesbill geranium.

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Hardy geraniums are fantastic for pollinators such as bees and hoverflies. Some of them flower until the first frosts, providing a long season of nectar and pollen.

What’s the difference between geraniums and pelargoniums?

All plants have a species or Latin name, as well as a common name. The botanical name for cranesbill geraniums is Geranium. However, 'geranium' is also the common name for the species Pelargonium. Despite sharing a common name, geraniums (pelargoniums) and cransbills (geraniums) are different species, and have different growing requirements.

Looking for pelargonium geraniums? See our geraniums Grow Guide.

How to grow hardy geraniums

Grow hardy geraniums in moist but well-drained soil in sun or shade. Cut back after flowering to encourage a second flush of blooms. Hardy geraniums die back in autumn and regrow in spring. Mulching annually with leaf mould or well-rotted compost or horse manure will keep plants growing well for several years.

Growing hardy geraniums: jump links

Follow our detailed advice on growing hardy geraniums, below.


Where to grow hardy geraniums

How to grow hardy geraniums - hardy geranium growing between paving slabs

Most hardy geraniums thrive in light shade, whilst the smaller alpine types do best in full sun. Hardy geraniums can cope with any soil type and some, such as Geranium sylvaticum and its cultivars, can cope with very dry conditions.

Hardy geraniums can be great self-seeders and plants will often grow in tiny cracks in paving, proving how tough they are.


How to grow hardy geraniums

How to grow hardy geraniums - potting on bare-root geraniums

Hardy geraniums are often bought potted but they can also be purchased online as bare-root plants. If buying bare-root geraniums, pot them up as soon as they arrive, and then plant them out a few weeks later, when they've put on growth. There's no need to improve soil unless it’s very poor.


Where to buy hardy geraniums

Caring for hardy geraniums

How to grow hardy geraniums - cutting back geraniums
How to grow hardy geraniums - cutting back geraniums

Hardy geraniums need very little care. They’re not targeted by rabbits, and slugs and snails will eat other plants in preference. They can be cut back right to the ground after their first flush of flowers and will produce fresh foliage and more flowers in the same summer. Some hardy geraniums offer attractive autumn foliage, so resist the urge to cut back too quickly after flowering.

Watch our No Fuss video guide to cutting back hardy geraniums, featuring Rosie Yeomans:


Propagating hardy geraniums

How to grow hardy geraniums - propagating geraniums
How to grow hardy geraniums - propagating hardy geraniums

There is seldom a need to propagate hardy geraniums as seedlings are easily lifted and potted up from the garden. Plants can be lifted and divided in spring. Growing hardy geraniums from seed can be tricky and long-winded.


Growing hardy geraniums: problem solving

Geranium sawfly damage on hardy geranium leaves

Hardy geraniums are mostly trouble-free. However they can be attacked by the larvae of geranium sawfly (Ametastegia carpini). These look like tiny grey caterpillars, around 12mm long. They munch holes in the leaves, leaving an unsightly, lace-like appearance. The more hardy geraniums you have in your garden, the more likely they are to breed.

The larvae can be hard to spot, as they drop off the leaves when the plant is disturbed. They are mostly active in May and September; the September generation pupates in the soil and overwinters, emerging in spring to lay eggs on the foliage. Although the damage can be very unsightly, it rarely weakens the vigour of the plant. The following actions might help to keep them under control:

  • The larvae of many geranium sawfly overwinter in the soil, so cultivating the ground beneath susceptible plants by clearing debris and lightly raking the soil will expose the larvae to be killed by frost, and to be eaten by birds and other predators
  • Check the undersides of leaves carefully from May onwards for signs of the eggs and larvae and remove by hand if possible, to avoid numbers building up

Advice on buying hardy geraniums

  • Hardy geraniums range in size and spread so make sure you buy the right plant for the space you have in mind
  • Hardy geraniums are available from garden centres but you'll find a greater range at specialist nurseries, and online
  • Always inspect plants for signs of damage or disease before buying or planting

Where to buy hardy geraniums


The best hardy geraniums to grow

1

Geranium x oxonianum

Geranium oxonianum f. thurstonianum
Geranium oxonianum f. thurstonianum

Geranium x oxonianum f. thurstonianum bears single to double, pink-purple flowers with very narrow petals. It’s perfect for growing at the front of a mixed herbaceous border, or at the base of shrubs such as roses.

H x S: 50cm x 70cm.

2

Geranium sanguineum var. striatum

Geranium sanguineum var. striatum
Geranium sanguineum var. striatum

Geranium sanguineum var. striatum is a compact, very low-growing geranium, which bears masses of pale pink, veined flowers in contrast with dark green foliage. It’s perfect for growing at the front of a mixed herbaceous border, or in containers on the patio.

H x S: 10cm x 30cm.

3

Geranium ‘Patricia’

Geranium ‘Patricia’

Black-centred, bright-purple flowers of hardy geranium Geranium ‘Patricia’ bears bright purple flowers with black centres over a low-growing mound of dark green leaves. Leaves turn a fantastic shade of red in autumn.

H x S: 60cm x 45cm.

4

Geranium cinereum 'Giuseppe'

Geranium 'Guiseppe'

Geranium cinereum 'Giuseppe' is a compact variety that remains as a neat cushion. From early to late summer the plants are covered with half inch-wide, bowl-shaped magenta flowers.

H x S: 30cm x 30cm.

5

Geranium ‘Max Frei’

Geranium ‘Max Frei’

Geranium ‘Max Frei’ bears bright pink, veined flowers on hairy stems, from June to August. Grow it at the front of a mixed herbaceous border, and deadhead spent blooms regularly to prolong flowering.

H x S: 40cm x 35cm.

6

Geranium 'Rozanne'

Hardy geranium 'Rozanne'
Geranium 'Rozanne'

Named after nurserywoman Rozanne Waterer who discovered this attractive hardy geranium with her husband Donald, Geranium 'Rozanne' bears large violet-blue flowers with white centres and grey anthers, for months on end.

H x S: 30cm x 60cm.

7

Geranium x magnificum

Geranium x magnificum
Geranium x magnificum

Geranium x magnificum produces a glorious show of rich violet-blue flowers in mid-summer. The Royal Horticultural Society have given their prestigious Award of Garden Merit (AGM).

H x S: 60cm x 90cm.

8

Geranium 'Spessart'

Geranium 'Spessart'

A pink-flowered plant is sometimes sold under the name 'Spessart' but the true plant has white flowers. It makes a useful ground cover plant for dry, shady areas, producing a dense mat of aromatic leaves, which take on rich autumn tints.

H x S: 50cm x 60cm.

9

Geranium maderense

Geranium maderense
Geranium maderense

Geranium maderense is the largest of the geranium species, reaching a lofty 1.5m in height. Although perennial, it often acts as a biennial, producing pretty magenta pink blooms in its second year.

H x S: 100cm x 150cm.

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