Hardy geraniums: Plant, grow and maintain

Botany

The hardy geraniums comprise nearly 400 species and over a thousand horticultural varieties! They are generally perennial plants, sometimes annual or biennial. Their foliage is often deciduous, but can also be evergreen or semi-evergreen. They are quite hardy and vigorous.

Found on almost every continent, hardy geraniums have a wide global distribution. There are many species in the mountainous areas of temperate regions and in the eastern Mediterranean (Balkans, etc.). They are easily encountered in the wild in France, which explains their good hardiness. Thus, except for the Madeira geranium, they are well-suited to the French climate! The most common in the wild in France is undoubtedly the Herb-Robert geranium (Geranium robertianum), which you will find at the edges of paths or woods, or on old stone walls. Unlike the geraniums cultivated in gardens, it has an annual or biennial life cycle.

Hardy geraniums are often confused with pelargoniums, which are commonly found in window boxes. The latter are incorrectly referred to as “geraniums.” However, pelargoniums have irregular flowers (the upper and lower petals are not the same shape), are much less hardy, and their leaves and stems are much thicker. They mainly originate from South Africa, while perennial geraniums are found in temperate zones!

Hardy geraniums offer a beautiful range of colours! From top to bottom: Geranium ‘Patricia’, Geranium ‘Salomé’, Geranium ‘Rozanne’ and Geranium cinereum ‘Jolly Jewel Salmon’

The geranium belongs, along with pelargoniums and erodiums, to the family of Geraniaceae, which it has given its name, and which comprises nearly 800 species. Etymologically, geranium comes from the Greek geranos, meaning crane, because its fruits resemble the beak of a crane. This is also why this plant is commonly known as Cranesbill. Interestingly, the names of Erodium and Pelargonium refer, respectively, to the beaks of herons and storks!

Hardy geraniums form clumps that are more or less compact or mats of leaves, making them good ground covers. They sometimes grow in upright clumps, like Geranium psilostemon. Their height varies greatly: many varieties measure 20 to 30 cm tall, sometimes up to 60 cm… and even up to 1.50 m for the Madeira geranium (but that is an exception!)

The flowers of hardy geraniums are most often simple, with five petals. They measure 2 to 6 cm in diameter. This is a rather classic flowering, yet delicate at the same time. The petals are quite broad and sometimes notched at their tips. The flowers can be double, like those of Geranium himalayense ‘Plenum’, giving them a much more sophisticated appearance. Depending on the fineness of the petals, they can take on a star-like shape, like the Geranium ‘Catherine Deneuve’.

The flowers come in beautiful shades of pink, mauve, blue or white. They can also be dark, purple, like in Geranium phaeum. They are sometimes bicoloured: the centre is then a slightly different colour, either darker (even black, in the case of Geranium psilostemon), or lighter, creating a lovely contrast. They often have darker veins radiating from the centre. The flowers of Geranium versicolor are striking with their pronounced veins standing out on white petals, creating a lace-like appearance!

Geranium pratense: botanical plate

Hardy geraniums can flower from spring to autumn, depending on the varieties. They sometimes offer an initial flowering at the end of spring, followed by a second in late summer. This resurgence of flowering is encouraged by summer pruning. Some, like the geranium ‘Patricia’, can flower for more than six months!

Hardy geraniums have decorative foliage, often quite finely divided. The leaves are palmately shaped, with rounded or sharper and finer segments. Those of Geranium renardii are very rounded and not deeply divided, while those of Geranium sanguineum are deeply divided. They can be aromatic, as in Geranium macrorrhizum, and then release a lemony scent when crushed. They are sometimes villous and sticky, as in Geranium macrorrhizum.

Although it is green in most varieties, the foliage can also take on a very dark purple hue, as in Geranium pratense ‘Purple Ghost’. The leaves sometimes display stunning colours in autumn, red, orange or bronze. This is the case for Geranium macrorrhizum, Geranium wlassovianum and Geranium sanguineum.

The diversity of hardy geranium foliage! From left to right: Geranium maculatum, Geranium renardii, Geranium ‘Bob’s Blunder’ and Geranium nodosum (photo Benjamin Zwittnig)

Most varieties are deciduous, but there are also evergreen geraniums. This is the case for Geranium x cantabrigiense or Geranium cinereum. Others retain their foliage only in a mild climate and lose their leaves in the event of a harsh winter.

The fruits of Geranium rotundifolium (photo Pancrat)

The fruits of the geranium, very fine and elongated, have the shape of a crane’s beak. They are surprising because, at maturity, a tension system allows them to suddenly eject the five seeds they carry, up to several tens of centimetres!

Some varieties have rhizomes that allow them to spread. Geranium macrorrhizum owes its name to its very thick rhizomes. Others have a single central stump, which remains in place and does not sucker (only the stems spread to cover the ground). Some geraniums form tubercles, which gives its name to the tuberous geranium (Geranium tuberosum). They have the particularity of flowering in spring and entering dormancy in summer.

Species and varieties

The most popular varieties

Our favourite varieties

Other varieties to discover

Geranium Dragon Heart

Very floriferous, this geranium bears large magenta flowers, contrasted by black at the centre, reaching up to 6 cm in diameter. It is remarkable for its long flowering period, from spring to autumn, and its colours of rare intensity. It makes a good ground cover, but it also adapts well to pot cultivation.

• Flowering time July to November
• Height at maturity 60 cm

See the product sheet

Geranium Rozanne

Among the best hardy geraniums, this variety offers a superb flowering that lasts nearly six months! It bears beautiful blue flowers from late spring until frost. Vigorous and easy to grow, it tolerates drought, sun, and partial shade. It also makes a good ground cover!

• Flowering time July to November
• Height at maturity 25 cm

See the product sheet

Geranium Orion

This variety has beautiful blue-violet flowers. It spreads quickly and makes a very good ground cover. Don't hesitate to grow it in a pot: its very long stems will cascade over the edge! It needs to be pruned in summer to provide a second flowering in autumn.

• Flowering time July to December
• Height at maturity 60 cm

See the product sheet

Geranium Patricia

This is a geranium with superb bright pink flowers, contrasted with black at the centre. Its leaves are deeply cut and turn red in autumn. It offers a very long flowering period, from spring to autumn. It enjoys cool soils but can withstand drought. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time July to December
• Height at maturity 50 cm

See the product sheet

Geranium Johnsons blue

This geranium bears delicate sky-blue flowers, lighter at the centre. They are quite large, measuring 5 cm in diameter. Its foliage is deeply cut. Quite compact, it spreads easily to form large carpets of leaves. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time June to September
• Height at maturity 50 cm

See the product sheet

Geranium magnificum

This geranium offers a generous flowering of blue-violet, delicately veined with purple. Easy to grow, it tolerates heavy or poor soils! Its leaves take on superb orange-red hues in autumn. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time July, August
• Height at maturity 60 cm

See the product sheet

Geranium nodosum Clos du Coudray

Very floriferous, this remarkable geranium offers a delicate mauve flowering from spring to autumn. Its petals provide a beautiful contrast between darker veins and a paler, soft pink edge. Suitable for shady situations, it will thrive in woodland accompanied by ferns, etc.!

• Flowering time July to October
• Height at maturity 50 cm

See the product sheet

Geranium macrorrhizum Spessart

This is a vigorous variety with delicately pink-tinged white flowers. It bears aromatic and evergreen leaves, which take on an orange-red hue in autumn. It makes a good ground cover for shady situations. It can even naturalise!

• Flowering time June, July
• Height at maturity 30 cm

See the product sheet

Geranium sanguineum Album

This geranium offers a superb flowering of pure white! It stands out well against the very finely cut dark green foliage. Enjoying sunny exposures and well-drained soils, it adapts well to rockeries. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time July to October
• Height at maturity 25 cm

See the product sheet

Geranium pratense Splish Splash

This very original geranium bears white flowers that seem splashed with mauve spots! It has large, deeply cut leaves. It offers a summer flowering, but if you cut it back at the end of this, it may possibly flower again in early autumn.

• Flowering time July to September
• Height at maturity 50 cm

See the product sheet

Geranium psilostemon - Armenian Cranesbill

This geranium bears superb magenta flowers with a black centre. We love it for its intensity! The leaves turn red in spring and autumn. Growing in an upright tuft, it is taller than most varieties. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS). It is native to the Balkans and Italy.

• Flowering time July to September
• Height at maturity 80 cm

See the product sheet

Geranium maderense

The Madeira geranium is exceptional for its size and generous pink flowering, borne on purple and villous peduncles! It forms a true trunk, making it much taller than other varieties! It also has beautiful large, cut leaves. Its only drawback is that it is not very hardy... Unless you live in a Mediterranean region, you will need to grow it in a pot and bring it in for winter.

• Flowering time June, July
• Height at maturity 1,20 m

See the product sheet

Geranium versicolor

An uncommon geranium that bears remarkable white flowers, tinged with fine purple veins, giving it a lace-like appearance, from late spring to autumn! Its compact and spreading habit makes it a good ground cover. It is semi-evergreen.

• Flowering time June, July
• Height at maturity 30 cm

See the product sheet

Geranium psilostemon Catherine Deneuve

This is a vigorous geranium that bears star-shaped flowers, magenta pink with black veins. Its very fine petals give it a different appearance from other geraniums. Moreover, it is evergreen! Use it as a ground cover.

• Flowering time June to September
• Height at maturity 50 cm

See the product sheet

Geranium Ann Folkard

This geranium has very bright leaves, light green tending towards yellow, becoming darker over the season. It offers superb magenta flowers with a black centre. Its long stems allow it to form a good ground cover or to climb on a bush if you plant it at its base! It enjoys rich, cool soils and sunny exposures.

• Flowering time July to November
• Height at maturity 40 cm

See the product sheet

Geranium cinereum Jolly Jewel Salmon

A surprising geranium with its intense and vivid colour, rose red, darker at the centre! Its flowers are beautifully veined with dark red, almost black. Enjoying poor, well-drained soils, it is perfect for integrating into a rockery.

• Flowering time July to September
• Height at maturity 20 cm

See the product sheet

Are you finding the choice complicated? Let yourself be guided by our advice sheet: “Hardy geraniums: how to choose them?”

Planting hardy geraniums

Where to plant?

Most hardy geraniums thrive in sun or partial shade. The species best suited for shaded areas are Geranium nodosum, which can even tolerate dry shade, and Geranium maculatum, which prefers more humid soil.

Hardy geraniums are rather undemanding regarding soil type. Generally, they favour fairly rich and humus-bearing soils that are relatively light. The soil should be well-draining but remain cool in summer. Avoid waterlogged areas, as hardy geraniums do not like excess water. They appreciate neutral or slightly acidic soils. Geranium sanguineum seems to be one of the most accommodating: it tolerates poor, dry, stony soils.

When to plant?

You can plant hardy geraniums in spring, after the last frosts, or in autumn.

How to plant?

We recommend enriching the soil with some compost. Maintain a distance of at least 40 cm between each plant to allow them space to develop properly. Plant compact geraniums, such as Geranium cinereum, more densely than those that spread and take up space (for example, the varieties ‘Rozanne’ or ‘Ann Folkard’).

• Place the root ball in a basin filled with water. This will help the plant establish.
• Dig a hole 2 to 3 times the size of the root ball, and add a few handfuls of compost or potting soil.
• Remove the plant from its pot. We recommend loosening the root ball a bit and gently untangling the roots, especially if they are pot-bound.
• Position the geranium.
• Replace the soil and gently firm it around the plant.
• Water.

Continue to water regularly in the weeks following planting. Your geranium will bloom within the year!

Pot planting:

You can plant your hardy geraniums in pots or window boxes. Some varieties produce long stems that will cascade over the edge of the pot! Feel free to plant other plants alongside them.

Start by preparing the substrate by mixing potting soil with a bit of sand. Choose a pot that is deep enough. Place clay balls at the bottom to allow for drainage. Add the substrate, then position the root ball. Cover with soil and firm down. Water.

The Geranium ‘Azure Rush’ in a pot (copyright Blooms of Bressingham)

To learn everything about planting hardy geraniums, check out our advice sheet: “How to plant hardy geraniums”

Maintenance

Once established, geraniums require very little maintenance! They are low-maintenance plants that manage well on their own. Their dense foliage has the advantage of preventing weeds from growing!

Geraniums are resilient plants, rarely suffering from diseases or pest attacks. However, they can be affected by powdery mildew. This fungal disease is characterised by a white fluff covering the leaves and stems. It develops in shaded areas of the garden, during warm and humid weather, or when plants are too densely planted. Cut away the affected parts, avoid wetting the foliage when watering, and if necessary, treat by spraying sulphur. Also, be cautious of slugs, which tend to nibble on young shoots. Scatter ash around your plants to create a barrier. Geraniums can occasionally be attacked by the larvae of otiorhynchus and by sawflies.

If you have planted them in a pot, we recommend watering at least once a week, or a bit more during the summer. Allow the medium to dry out between waterings: excess moisture can cause the roots to rot.

Geraniums planted in the ground do not need fertiliser. Add a bit of compost in autumn, around the clump, especially if your soil is poor. If you are growing it in a pot, we recommend adding a bit of liquid fertiliser every two to three weeks.

How to prune:

In mid to late summer, once the flowering is finished, prune severely to rejuvenate the plant. Remove the faded stems and damaged foliage. This encourages the development of new vigorous shoots, more decorative foliage, and promotes a second flowering, while preventing the plant from self-seeding. Pruning the geranium also helps control its growth and keeps it more compact. You can also remove dead stems and leaves at the end of winter, cutting the plant back to ground level.

However, some geraniums, such as Geranium macrorrhizum, do very well without pruning.

Geranium ‘Karen Wouters’

Multiplication

Not all hardy geraniums propagate in the same way. Some techniques are more or less suitable depending on the varieties. Reserve sowing for botanical species; for horticultural varieties, prefer propagation by cuttings or the division for those that spread through their rootstocks or stolons.

Sowing

It is possible to multiply geraniums by collecting and sowing the seeds, but it is better to reserve this technique for botanical species. For horticultural varieties, the results are quite unpredictable, and there is little chance that the flowers will be identical to those of their parents. Some hybrids, such as ‘Johnson’s Blue’ or ‘Patricia’, are even sterile.

Geraniums (notably endressii, oxonianum and pratense) tend to self-seed easily! You can remove the faded flowers to prevent spontaneous sowing, or choose to let them self-seed freely. Collect the seeds by cutting the fruits when they are ripe.

You can sow the seeds at autumn, just after collecting them. The germination rate is higher when they are sown fresh, but it is also possible to store them for sowing in spring.

• Fill a pot with special sowing compost, then lightly firm it down.
• Sow by scattering the seeds on the surface.
• Cover with a thin layer of compost.
• Water.
• Place the pot under a frame, out of direct sunlight.

Continue to water regularly to keep the substrate moist. The seeds will germinate in spring. As soon as the seedlings have several leaves, you can repot them, then plant them in the ground once their root system is sufficiently developed. Depending on the different varieties, you will need to wait one to two years for the geraniums to start flowering.

Tuft Division

The method of propagation depends on the behaviour and morphology of the plant: those that spread by producing rootstocks or stolons are easy to multiply by division. The more compact ones (for example, Geranium cinereum) or those with a taproot are less suitable for this technique. In this case, propagation by cuttings is preferred.

The advantage of division is that it allows for easy production of new plants. The best time to divide geraniums is in spring, in April or May. Do this on average every four years to rejuvenate the clumps.

Start by digging up the clump. Then divide it by hand or with a spade, to obtain several clumps, each with enough roots. Dig a planting hole and add a few handfuls of compost. Plant them in their new location, then water.

For more information, check our advice sheet “Hardy Geraniums: How to Divide Them”

Propagation by Cuttings

You can propagate the geraniums in spring, around April. This is an interesting technique for varieties that do not lend themselves to division or sowing. Propagation by cuttings works very well for Geranium macrorrhizum!

Prepare a pot by filling it with substrate, then take a segment of the basal stem. Leave only one or two leaves on the cutting, remove the others and any flowers or flower buds. Plant the cutting, then gently firm it down to ensure good contact between the stem and the substrate. Water. Place the pot in a bright location but out of direct sunlight, at a temperature between 20 and 25 °C, and ensure that the substrate remains moist until rooting occurs. The cuttings root quickly, and the new plants can flower within the year!

The geranium nodosum ‘Clos du Coudray’

Association

With its generous flowering and decorative foliage, the hardy geranium easily finds its place in a colourful mixed border, typical of English gardens! Its soft hues bring a natural and romantic touch. It pairs wonderfully with roses, delicately dressing their often bare base. The colours of the geraniums and roses harmonise perfectly! It will also reduce maintenance and the need for weeding at their base. Similarly, the hardy geranium is a good ground cover that adds colour at the base of trees and bushes.

The rose ‘Lady of Shalott’ with the hardy geranium ‘Rosemoor’ (copyright Biosphoto Friedrich Strauss)

The hardy geranium has nothing to envy from the pelargonium, the “king of balconies”. Planted in a pot or window box, it beautifully colours window sills and terraces! Some varieties like ‘Azure Rush’ or ‘Ann Folkard’ have long stems that cascade over the edge of the pot.

The pink, blue, or white flowering of the geranium creates a romantic and delicate atmosphere. It is perfect for accompanying roses, but also for integrating into a flowerbed alongside astrantias, sages, stachys, or alliums. It can also be part of a cottage garden, with lush vegetation and soft tones. Its rather understated flowering and broad foliage will bring a very natural feel!

Depending on the varieties, geraniums are excellent understorey plants (e.g. Geranium nodosum) associated, for example, with ferns, while dwarf varieties like Geranium cinereum or Geranium dalmaticum are good rock garden plants, suited to sunny and drier conditions.

A colourful scene along a path with Geranium ‘Johnson’s Blue’, Alchemilla mollis, Phlomis russeliana, and Centranthus ruber (copyright GAP Photos Elke Borkowski)

… and many more ideas in our association sheet “Pairing Hardy Geraniums”