<em>Pelargonium</em>, geranium: to plant and to grow
Contents
Pelargonium in a nutshell
- Pelargonium offers long, generous flowering for much of year, from May until first frosts
- Always beautiful, low-maintenance, pelargonium flowers offer wide diversity of colours from pastel to vivid
- Foliage sometimes variegated, often scented with rose, lemon, apple and even chocolate notes that help keep mosquitoes away!
- Frost-tender, it is grown as an annual in open ground or in pots and overwintered indoors: suitable for all regions
- King of balconies, hanging baskets and window boxes, it is also exceptional in beds and borders
A word from our expert
What would our window sills, balconies, summer beds and borders be without Pelargonium, more commonly called geranium?
Unlike its cousin the hardy geranium, Pelargonium is a non-hardy plant, tender, generally grown as an annual unless brought indoors for winter protection from frost. Growing in open ground is only possible in mildest regions.
That matters not! It offers a wide diversity of shapes, colours, textures and scents, to the point of provoking acute collection fever!
Pelargonium is available in many varieties such as pelargonium zonale with velvety leaves marked by a darker zone, the ivy geranium (Pelargonium peltatum) “king of balconies”, which forms flowering cascades all summer, the florist’s pelargonium with large flowers or the scented pelargonium such as rose geranium (Pelargonium graveolens), whose leaves rich in essential oils give off varied scents of rose, lemon, mint or even chocolate depending on cultivar and are said to repel mosquitoes.
While leaves of scented pelargonium are edible, its root is also used in herbal medicine for its cleansing benefits.
It has a long and generous flowering lasting six months of the year (even longer if kept warm over winter), ranging from pure white to the most brilliant red, only interrupted by first frosts of autumn.
Sometimes elegant, sometimes bordering on garish, it is at home in all gardens whatever their style — in beds, borders, rockeries, containers and hanging baskets.
Always beautiful whatever the weather, geranium flowers only need sun and a few regular waterings.
From maintenance to pruning, discover our tips and fall for our exceptional collection of pelargoniums in mini plugs or for our geranium seeds so easy to sow! So why miss out?
Description and botany
Botanical data
- Latin name Pelargonium
- Family Geraniaceae
- Common name Pelargonium, Scented geranium, Florist geranium, Balcony geranium
- Flowering from April–May until autumn
- Height 0.15 to 1 m
- Exposure sun or partial shade
- Soil type all, well-drained
- Hardiness frost-tender
The Pelargonium, better known as geranium, is a perennial or an undershrub belonging to family Geraniaceae.
Native to mountainous regions of South Africa, Pelargonium is not hardy in our climates and is generally grown as an annual on terraces or balconies, unlike its cousin hardy geranium which is a hardy species that can remain in the ground in our gardens. Pelargonium is moreover incorrectly called “geranium”. Geraniums and Pelargoniums are two distinct species, although they belong to the same family. Nevertheless, using the name “geranium” for pelargoniums has remained common.
Genus Pelargonium includes about 230 species and nearly 1,000 varieties. Many cultivars and hybrids have been obtained from around twenty species including Pelargonium grandiflorum, the florist pelargonium (Pelargonium x domesticum), Pelargonium graveolens or rose-scented geranium, the most fragrant of all used in perfumery, which is at the origin of many hybrids, Pelargonium fragrans, with a pine scent, Pelargonium crispum, Pelargonium peltatum or ivy geranium, nicknamed the “King of Balconies” for its trailing habit.
Today very few botanical pelargoniums remain because of extensive hybridisation. Most cultivars fall into four main groups: ivy pelargoniums, with strongly trailing stems much appreciated in hanging baskets or window boxes; zonal pelargoniums (Pelargonium x hortorum), classic upright types widely used in beds; “Regal” or large-flowered pelargoniums; and scented pelargoniums or rose geraniums, also called “scented geraniums”, whose leaves are aromatic.
There are also pelargoniums known as “Unique” which are undershrubs that can reach 1 m in height in one season and whose foliage exudes a strong, pungent spicy scent at the slightest touch.
Botanical illustrations: Pelargonium grandiflorum / Pelargonium graveolens / Pelargonium peltatum
With a rapid growth rate, the plant forms a bushy, dense clump, almost as wide as tall, with size varying considerably from 0.10 m in height for dwarf and miniature varieties to 1.20 m for the largest pelargoniums. Some geraniums resemble a small shrub with a spreading habit.
Habit varies by variety, erect for zonal geranium which forms a compact or very spreading bush, and trailing for the famous ivy geranium. Stems can reach 1 m in length.
Branched stems bear leaves that also vary in shape: alternate, fleshy, rounded, lobed or pointed, deeply veined, velvety or glossy, with dentate or undulate margins. Leaves are for the most part evergreen in regions spared from winter frosts.
They are leathery, smooth and shiny, similar to ivy leaves on ivy pelargonium, fan-shaped, funnel-shaped in Pelargonium cucullatum, and sometimes so lobed that they recall maple leaves.
They often have a long petiole, measure 1 to 15 cm in diameter and show every shade of green: bright green in ivies, medium green, tender green sometimes variegated with cream-white, gold or silver, or green-grey margined with red. Leaves can be bicoloured or tricoloured. Many varieties with decorative foliage exist such as ‘Mrs Pollock‘ and ‘Vancouver’, popular with collectors.
The zonal geranium (notably cultivars like ‘Fantaisie’) is distinguished by round, often zoned leaves (hence “zonal”), sometimes superbly margined with a lighter tone and especially marked with colour halos arranged in irregular concentric rings of brown, dark bronze green, slate blue or black or in “butterfly-wing” patterns, with a distinct tone at leaf centre.
Diversity of foliage in Pelargoniums
Foliage of scented pelargonium, rich in essential oils, is strongly aromatic: leaves, rougher or softer, plicate, often deeply incised, release a variety of scents at the slightest crush — rose-lemon, green apple, lemon, citronella, orange, mint, eucalyptus, pine in Pelargonium fragrans, spices and even hazelnut, chocolate or carrot! Pelargonium x graveolens and rose-scented pelargoniums (P. capitatum), with rose fragrance, are much prized in perfumery.
This aromatic foliage is said to repel mosquitoes.
Leaves are edible and can flavour fruit salads.
Overwhelming the foliage, flowering, often particularly long and abundant, occurs from April to October depending on species or throughout the year for plants kept between 10 and 15°C. Pelargonium produces masses of single, semi-double or double flowers as attractive in bud as when fully open.
At stem tips, flowers cluster in terminal umbels of varying size, renewing all summer and providing a strong contrast with foliage.
Shape varies by species: zonal pelargoniums have large flower heads, single or double, forming splendid spherical clusters 5 to 13 cm in diameter that stand out clearly from foliage, while ivy and scented geraniums produce countless smaller flowers grouped in looser, less imposing umbels. Flowering of aromatic-leaved pelargoniums is less spectacular but more discreet and delicate.
Some flowers: Pelargonium peltatum ‘Big 5 White Angel’, Pelargonium ‘Mosquitaway Eva’, Pelargonium graveolens, Pelargonium cucullatum, Pelargonium ‘Paton’s Unique’ and Pelargonium ‘Wilhelm Langguth’
Flowers, composed of at least 5 to 6 petals, are cup-shaped, star-like, trumpet-shaped, funnel-shaped or butterfly-shaped (top two petals larger than the three lower petals) and measure 1 to 4 cm in diameter. Some resemble small roses (Pelargonium hortorum ‘Appleblossom’) or even dahlia-cactus flowers with twisted, rolled petals, or have narrow pointed petals with cut edges (Fireworks ‘Scarlet’).
Summer colours are varied and not limited to the traditional bright red geranium; they range by variety in single or multicoloured shades, vivid, rare, deep or pastel from claret, fresh pink, mauve, purple, pure white, more rarely yellow to salmon-orange. These bright or velvety colours do not fade under the sun.
Some petals are veined, variegated in subtle bicolours or sometimes tricolours, showing small maculations with varying contrast.
After flowering, flowers give way to fruits shaped as a very elongated bird’s beak, hence the name “pelargonium” which in Greek means “stork”.
Typical bird-beak-shaped fruits
Flower of scented pelargonium, slightly fragrant, is edible and can decorate summer desserts such as sorbets.
Not hardy, pelargonium is somewhat tender and should be brought into a greenhouse in regions with cold winters. Drought-tolerant, it grows quickly in light, well-drained fertile soils, in full sun or preferably in partial shade in hot regions.
Geranium is the must-have annual for summer displays, bringing structure and colour to beds, borders and sunny edges, as well as hanging baskets and window boxes on terraces, balconies or in conservatories.
For centuries, pelargonium root has been used in herbal medicine for its beneficial, sanitising properties against symptoms of respiratory infections such as bronchitis.
Main species and varieties
Not always easy to find your way among the 230 species of pelargoniums! First distinguish the Pelargonium, which is frost-tender and grown in our latitudes as an annual, from the hardy geranium, which is hardy and can remain in the ground for years in the garden.
Pelargonium is wrongly called “geranium”. It was the botanist Carl von Linné who, in 1787, grouped Pelargoniums and Geraniums under the same genus. About 25 years later the French botanist L’Héritier realised the mistake and created the genus Pelargonium. Too late! the mistake persisted for a long time… These two plants do belong to the same family, Geraniaceae, but that is their only point in common!
You can distinguish several groups of pelargoniums, within which numerous cultivars have been created. That doesn’t count the hybrids! They are adapted to every use and come in a multitude of colours, offering a great diversity of textures and scents!
- The Pelargonium zonale (30 to 50 cm tall): The classic geranium, forming colourful mounds with upright stems, beautiful round velvety leaves marked by a contrasting halo and large flower heads in every shade of red, pink and white, solid or bicoloured. It belongs to the large group of hybrids Pelargonium x hortorum. Used in beds and window boxes.
- The ivy-leaved pelargonium (up to 1 m tall): Known as the “king of balconies”, most used in pots, in window boxes or hanging baskets. It forms cascades of trailing or creeping flowers. Its glossy bright green leaves evoke ivy.
- The Pelargonium with scented foliage: Its flowering is more discreet, its foliage rough or velvety and sometimes variegated with yellow or silver, and above all it gives off varied scents of apple, mint, spices, lemon or orange when crushed. P. x graveolens and P. capitatum emit a rose perfume, widely used in perfumery.
- The florist’s or large-flowered pelargonium (Pelargonium grandiflorum): Also known as Regal pelargoniums. It resembles Pelargonium zonale but has dentate leaves and much larger inflorescences. Often grown indoors or in a greenhouse.
Discover our unique collection of geraniums as plug plants or as seeds, including some exclusive varieties!
Pelargonium peltatum Balcon Imperial Red
- Flowering time June to December
- Height at maturity 20 cm
Pelargonium Brocade Mrs Pollock
- Flowering time June to November
- Height at maturity 45 cm
Pelargonium graveolens
- Flowering time July to October
- Height at maturity 60 cm
Collection of 10 Red and Pink Balcony Geraniums
- Flowering time August to December
Pelargonium peltatum Ruby
- Flowering time July to December
- Height at maturity 50 cm
Pelargonium hortorum Fireworks Pink
- Flowering time June to November
- Height at maturity 40 cm
Pelargonium Border Supreme F2 Seeds - Geranium
- Flowering time August to November
- Height at maturity 35 cm
Pelargonium hortorum Flower Fairy Velvet
- Flowering time June to November
- Height at maturity 35 cm
Pelargonium Cassiopeia
- Flowering time June to November
- Height at maturity 50 cm
Pelargonium Blanche Roche - Ivy Geranium
- Flowering time June to December
- Height at maturity 20 cm
Pelargonium crispum Variegatum
- Flowering time July to October
- Height at maturity 80 cm
Pelargonium Lemon fancy
- Flowering time July to October
- Height at maturity 60 cm
Discover other Pelargonium - Geranium
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Planting
Where to plant a pelargonium or geranium?
Pelargonium is a plant native to South Africa, sensitive to frost and therefore somewhat tender in our climates. Below 0°C, pelargonium will not survive.
If it can remain in ground in mild coastal climates and in areas spared severe frosts, retaining its leaves even in winter, it will simply need to be placed in an unheated greenhouse or conservatory at a minimum temperature of 10°C elsewhere or grown as an annual. You can therefore keep it from year to year by wintering it frost-free and bringing pots out again in the growing season.
Note that Elisabeth, our Mediterranean climate specialist, grows a Pelargonium quercifolium in ground. It has been there for five or six years, reaches over 1 m in height and readily resprouts from the stump when it has suffered a little frost. Finally, she never waters it!
Tolerant of soil conditions, naturally resistant to summer drought, unaffected by the elements, and content with a good, well-drained soil, it performs best in a rich, light soil.
From its South African origins, it has retained a taste for sun and heat. It thrives in full sun or in partial shade in southern regions.
You can plant your pelargoniums in ground or in pots.
With ornamental, sometimes scented foliage and its so-generous flowering, Pelargonium is indispensable in romantic, colourful or chic summer displays. Ideal in natural-style gardens.
Non-hardy, it is the star annual of summer displays, ephemeral in charm and to be replanted each year as desired. Long confined to hanging baskets and window boxes on window sills, balconies and terraces, pelargonium now features in borders, beds and sunny edging, where it quickly brings a very cheerful, colourful touch throughout the season.
Ivy geraniums with a trailing habit form flowering cascades perfectly suited to hanging baskets and rockeries and are excellent as groundcover. They can also be trained on a trellis against a wall outdoors or in a winter garden.
The zonal geranium grows in colourful, compact clumps and is ideal in beds, containers and borders.
The scented geraniumsare wonderful as a low hedge or border along a path or in a large pot on the terrace or in the conservatory, never too far from home to enjoy their scent.
Finally, all are well suited to greenhouse cultivation.
When to plant a pelargonium or geranium?
Planting pelargonium or geranium is done in spring but timing varies by region. In mild climates, you can plant our pelargoniums as plug plants from March–April. Wait until mid-May in the most northerly regions before planting out. Meanwhile, you can pre-cultivate them in pots in a warm, bright place to accelerate their growth.
In all cases, on receipt, pot up and keep under cover (conservatory, greenhouse…) at a temperature above 14°C and wait until risk of frost has passed and soil is well warmed before planting or moving outdoors.
How to plant a pelargonium?
- In ground
For a well-coloured massed effect, favour group planting. Count on 5 to 7 plants per m² and allow 20 cm between plants. It needs a light, humus-bearing but above all well-drained soil. Be sure to add gravel where water tends to stagnate.
- Loosen soil well
- Dig a hole two to three times the size of the plug plant
- Place the plug plant and cover without burying it too deeply, adding a little leaf mould
- Firm down without damaging the young plant
- Water well at the base
More advice on planting annuals as plug plants on our blog!
- Planting geraniums in pots or window boxes
All geraniums are kings of hanging baskets, window boxes, urns or containers, but ivy geraniums are most used. Use a well-draining mix to avoid stagnant moisture at the roots. Feel free to mix varieties for vibrant, floriferous combinations!
- In the base of a pierced container, spread a good drainage layer (gravel, broken pottery or clay pebbles)
- Plant in a potting mix for geraniums or in loam mixed with compost
- Place in sun
- Water regularly, never letting the growing medium dry out between waterings: compost should remain moist but never waterlogged
- Move potted pelargonium outside after frosts
When and how to carry out sowing of pelargoniums or geraniums?
Sow pelargonium seeds under cover from mid-January to mid-March. Young plants should be transplanted outdoors into ground once risk of frost has passed. They will flower in same year as sowing.
How to sow geranium seeds successfully
- Sow geranium seeds 2 cm apart without burying in a seed tray filled with sowing compost
- Cover with 1–2 mm of compost
- Place in warm spot at minimum 18°C, ideally 20–25°C
- Keep compost moist but not waterlogged
- Germination occurs in 10–15 days
- At four-leaf stage, prick out young plants into individual pots or buckets
- Mid-May, after risk of frost has passed, transplant into ground, into pots or planters
- Pinch tips of stems of young rooted cuttings early to encourage branching
Discover our tips to succeed with sowing annual seeds! and our advice sheet on Pelargonium propagation by cuttings
Maintenance, pruning and care
The Pelargonium is a very floriferous annual plant that grows without requiring much care.
In open ground, it tolerates lack of water quite well: water only during first weeks after planting.
Geraniums in pots should be watered one to three times a week but without excess, as soon as topsoil dries: substrate must remain moist.
Potted geranium is a heavy feeder, requiring weekly applications of liquid “geranium” fertiliser from April to August, to promote continuous growth and flowering.
Remove all first flower buds and pinch out tips of young plants to encourage their branching.
Regularly remove faded flowers and yellowing foliage to encourage new flowers and prolong flowering.
Pelargoniums do not tolerate frost. In autumn, lift plants grown in open ground, discard them or temporarily replant them in pots of same size or slightly smaller.
Bring pots indoors to a cool but bright, frost-free place to keep them from one year to the next.
→ Find out more about Pelargonium winter care in our tutorial!
How to keep geraniums over winter?
Pelargoniums or geraniums can continue to flower throughout winter if kept between 7 and 10°C in a bright room. To learn all about overwintering, see our care sheet: How to overwinter Pelargoniums (balcony geraniums) successfully
Potential diseases and pests
Pelargonium is susceptible to certain diseases and pests.
Cold and excess water can cause grey rot (botrytis) of the roots and base of the stems (blackleg). Zonal pelargoniums are susceptible to rust. In both cases, burn affected leaves and treat, if still possible, with Bordeaux mixture.
Against whiteflies (aleurodes), shower the foliage and keep slugs at bay naturally with our advice.
Its stems can also fall prey to the green caterpillar of a small brown moth called the Geranium bronze, quickly killing the plant. Cut off all affected stems.
Caterpillar and moth of the Geranium bronze (Cacyreus marshalli)
Also watch out for aphids that can invade it: shower plants with soapy water to dislodge them.
More details in our article : Diseases and parasitic pests of pelargoniums.
Propagation
Pelargonium or geranium is easily multiplied by propagation by cuttings. Cuttings taken in late summer will flower from following spring.
When and how to take a geranium cutting?
In July–August, choose a healthy pelargonium and take several cuttings.
- With pruning shear, cut a stem without flowers about 10 cm long just below a node
- Remove all lower leaves so only two upper leaves remain
- Cut the base on a slant and make a small incision with a sharp knife
- Place in a perforated container (you can also insert the cuttings into individual buckets) containing a mixture of turf and sand, inserting the cuttings to half their length and spacing them 10 cm apart
- Water copiously
- Close the container with a lid or a plastic bag
- Keep moist throughout winter, in a dry, bright room heated to 12–15°C
- At end of winter, pot them on into individual buckets
- Plant outdoors or move pots out around mid-May
→ Read also : How to propagate pelargonium or balcony geraniums?
Pairing pelargoniums
With their bright or pastel colours, Pelargoniums or geraniums cater to every desire, in ground or in pots to create displays often very colourful and very cheerful throughout summer.
Examples of uses: in window boxes with bright colours or in borders with pastel tones with Liriope muscari ‘Ingwersen’ or Carex-type grasses and small mat-forming Sedums such as ‘Cape Blanco’, ‘Purpureum’, ‘Album Superbum’, sieboldii, etc
They come in an infinite range of colours allowing endless combinations, in gradients or monochrome, elegant and chic or sparkling! They suit all garden styles, from the most romantic to the most naturalistic.
They pair well with many summer flowers, annuals or perennials.
In a refined summer border, pair zonal geraniums with white or pearly-pink flowers with purple ageratums, Buenos Aires verbena, and dense clumps of small mealy sages.
In a multicoloured flowerbed, mix geraniums with dwarf dahlias and marigolds (they will protect them from whiteflies).
They also go very well with plants with a lighter silhouette, such as Cleomes, Nepetas, tobaccos and cosmos.
An idea for a combination: Pelargonium ‘Mosquitaway Eva’, Lobelia ‘Hot Water Blue’ and Chamesyce hypericifolia ‘Diamond Frost’
Paired with petunias, ivy geraniums will hide the bare base of a shrub rose throughout summer.
At edge of a colourful summer bed, pelargonium flowers combine nicely with contrasting blooms of zinnias, rudbeckias, and with pointed silhouettes of phormiums and cordylines.
Intense colour of scarlet geraniums combines well with bronze or purple foliage of heucheras, castor oil plant, dahlias and tall cannas.
You can also intersperse them to punctuate borders of grey-foliaged plants such as cerastiums, Helichrysum, dusty miller or artemisia.
Ivy geranium can be trained against a conservatory wall, alongside other climbing annuals such as morning glories and ipomoeas.
Create magnificent pots and hanging baskets by combining them with Calibrachoa ‘Million Bells’, Bacopa, lobelias or scaevolas.
Useful resources
- Discover our scented geraniums: their foliage gives off scents of rose, lemon, mint, spices and even carrot, enough to send a squadron of mosquitoes packing!
- Whether ivy-leaved, zonal or scented, Geraniums or Pelargonium are generous plants, stars of gardens, terraces and balconies throughout summer — don’t miss out!
- With romantic or very vivid colours, they are essential for composing “Happy” scenes all through the season, take pride of place in a pink garden, in Catalan-inspired planting or simply in a white garden!
- Our advice on choosing an ivy-leaved geranium, king of flower-filled balconies all summer long.
- Discover our 7 pairing ideas to create beautiful summer window boxes
- Find our advice sheet: 10 scented pelargoniums
- Discover our tutorial: How to prune a Pelargonium?
Frequently asked questions
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Why are my geranium leaves turning yellow?
Not too much, not too little! That's the key rule for watering geraniums. If water is lacking, leaves yellow and drop; conversely, too much water harms flowering and plant health, and roots may rot. Geraniums grow best in a light, very free-draining, well-aerated and rich soil, both in garden and in pots. In pots, water your pelargoniums once a week. Pelargoniums in pots are fairly demanding and, if short of fertiliser, foliage can also yellow. Remember to feed them well throughout growth.
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