Geraniums (Pelargonium): Care and tips – Floralelle

Topic: Geranium, Pelargonium

Origin and growth
The geranium, which is called pelargonium, originates from South Africa – here alone there are more than 250 wild species of geranium. Especially many varieties can be found around the coastal region of Cape Town. The easy-care and heat-resistant plants can also be found in other countries: In Australia and New Zealand there are the species Pelargonium australe and Pelargonium indoroum, in Anatolia the species Pelargonium finlicherianum grows and in Iraq and in Iran the geranium species Pelargonium quercetorum can be found. It is not proven when or how exactly the first geraniums came to Europe. Around the 17th century merchants are said to have started to import the Pelargonium species. At that time they were mistakenly called Geranium and thus received the popular name Geranium. Only around 1789 the plants were assigned to the genus Pelargonium. In their home country and in our country, too, the diversity is hard to measure – and every year numerous new varieties are added. The geranium belongs to the family of the cranesbill family (Geraniaceae) and is distinguished in the United States first in three forms: Suspended geraniums (Pelargonium peltatum) and upright geraniums (Pelargonium zonale), which are usually long flowering and resistant varieties with large flowers. In addition, the scented geraniums, which are often used to obtain scented oils.

Geraniums are the most popular balcony and garden flowers because they do not need much care and flower through the whole summer. Geraniums bloom in a wide variety of colours: from white to pink, red or violet, everything is there. Often the flowers standing in umbels are also two-coloured or patterned with stripes or dark spots. The Mosaic Purple variety, for example, has beautiful striped and speckled petals. In order for geraniums to flower continuously until frost, they need cooler nights – this is especially true for noble geraniums. Pelargoniums grow bushy and have strong shoots. Depending on the variety, they carry beautifully patterned leaves. Upright geraniums are considered to be evergreen semi-shrubs and grow to a height of 25 to 40 centimeters. The hanging geraniums usually grow up to 30 centimeters high, but can form over 150 cm long, overhanging shoots. Their stems are slightly hairy and begin to lignify from below over time.
Attention poisonous! Geraniums are harmless to humans. However, animals such as hares, rabbits, guinea pigs and hamsters should not come into contact with these plants. For them they are poisonous and skin-damaging.

The different geranium groups
Geraniums are unbelievably complex and offer a lot of variety in growth form, leaf and flower. They can be divided into six groups, which in turn bring with them a number of different varieties.

Hanging geraniums
With their long flower cascades, Hänge-Geranie (Pelargonium peltatum) are the classics for lush balcony boxes. Particularly popular are robust, single flowering varieties such as from the ‘Cascade’ series or the well-known pink ‘Ville de Paris’. They’re growing fast. Semi-filled and stuffed varieties, on the other hand, grow more compactly. Since their flowers stick together during prolonged rain, a roofed location is favourable for them.
Fragrance Geraniums
With them the flowers do not play the main role, here the leaves are decisive! Scented geraniums are available in countless variations and each one surprises with a special aroma, for example ‘Chocolate Peppermint’ (chocolate), ‘Queen of Lemons’ (lemon), ‘Purple Unique’ (wine gum), ‘Bourbon’ (rose), ‘Lady Plymouth’ (peppermint), ‘Orsett’ (peppery-lemony) – great for flavouring food and drinks! Some scented geraniums are said to even deter mosquitoes with the help of their spicy aroma.
Fine geraniums
Originally noble geraniums (Pelargonium x grandiflorum) were houseplants. For some time now, they have also been enriching the balcony plant assortment with durable, less sensitive new cultivars. The special thing about them are their often large, beautifully drawn flowers. They grow upright and compact, typical are the serrated leaves at the edges. Clarion Violet’, for example, blooms pink with a dark eye, ‘Velvet Red’ in velvety purple. Noble geraniums are pleased about a protected place.
Standing Geraniums
The standing geraniums (Pelargonium x hortorum) are a delight with a huge variety of varieties. Most adorn themselves with semi-filled and filled flower balls in white, pink, violet, red, orange and pink tones, often with colour-intensive shining eyes like ‘Grandeur Light Pink Splash’. Stellar geraniums are new. They stand out with star-shaped flowers (‘Stellar’ and ‘Graffiti’ varieties).
Interspecific varieties
The standing geraniums (Pelargonium x hortorum) are a delight with a huge variety of varieties. Most adorn themselves with semi-filled and filled flower balls in white, pink, violet, red, orange and pink tones, often with colour-intensive shining eyes like ‘Grandeur Light Pink Splash’. Stellar geraniums are new. They stand out with star-shaped flowers (‘Stellar’ and ‘Graffiti’ varieties).
Leaf decoration geraniums
They are a subgroup of standing geraniums with colourful, beautifully drawn foliage. Leaf jewellery geraniums (Pelargonium x hortorum) have a long tradition, already in the 18th century they were cultivated in England. Beside their beautiful leaves, they carry pretty, dainty flowers. The new varieties include, for example, the varieties of the healthy ‘Pelgardini’ series.

With their beautiful flower carpets, geraniums are the most popular balcony plants. Their multitude of expressive blossoms ignites an enormous distant effect. Balcony boxes lavishly furnished with geraniums can be found especially on large farmhouses. But this easy-care classic also cuts a fine figure in the garden and on the terrace, in small and large containers, as a hanging basket and high trunk. The star-shaped geraniums, for example, are better placed in planters. With their dainty flowers that stand high above the foliage, they are a real embellishment for seating areas on the terrace or balcony. Angel sucking geraniums (“Angeleyes”) are also suitable for plant pots. They are particularly effective when used in small pots as table decorations. In addition you can use noble geraniums as houseplants. A good long-distance effect develops in particular with the correct plant partners. Almost all other hanging or upright balcony flowers match the geranium. The simplest combination for the flower box is two different coloured geraniums – a great colour harmony is created by pink and crimson varieties, for example. If you want to have more variation, you can use matching verbenas, soft smoke plants, snowflake flowers (Bacopa) or blue elf mirrors (Nemesia) as companions. There are hardly any limits to the creativity of the composition. It is best to make sure that the planting partners have similar characteristics. This will make it easier for you to care for them later. In Mediterranean style, the combination with herbs is an excellent eye-catcher. Herbs love, just like geraniums, warm temperatures and lots of sun. The grey-green of sage and rosemary or the blue tones of flowering lavender are a wonderful complement. Marguerites (Argyranthemum), standing geraniums and the white, elegantly overhanging marsh yarrow (Achillea ptarmica ‘Gipsy White’) form a great trio. Here you can find more design ideas with geraniums.

Planting and care
Large pots or large balcony boxes (20 x 100 centimeters) are ideal for geraniums. In these you can plant about five plants. For a good fertiliser and water supply, the box should be at least 18 centimeters high. Planters for geraniums should have a water drainage hole or good drainage, because sun worshippers don’t like wet feet at all. From the end of February, geraniums can be repotted into fresh soil and grow in a bright, cool window seat. In cold regions, geraniums are placed in good balcony flower or geranium soil only after the ice saints – in the middle of May. For this purpose own cuttings can be used. If you want to buy new geraniums, you should avoid the handle to seeds. This form of cultivation is long and laborious. We recommend young plants instead – these are available from spring onwards. Pelargoniums need many nutrients, especially during the growth phase. Therefore, you can make sure that the potting soil is well fertilised when you plant it. Three to four weeks after planting you should continue to fertilise at regular intervals.

Geraniums need a lot of water, but should not be kept wet all the time. Therefore, do not water until the earth has dried. If waterlogging occurs, this leads to large, brittle leaves and, in the case of hanging geraniums, to corking on the undersides of the leaves. In order to prevent rot or mould from forming on withered flowers in weeks with heavy rainfall, they should be regularly cleaned out. This also strengthens the formation of new flowers. The most easy-care geraniums are those of the Cascade group. Besides their reliable flowering and a great long-distance effect, these varieties are self-cleaning – cleaning is not necessary.

Pelargoniums require a nutrient-rich soil and are suitable for sunny to semi-shade locations. The following applies here: the more hours of sunshine, the more flowers are formed. A lukewarm breeze does no harm, but if the plants are too strong in the wind, the shoots can easily break off. Pelargonium species with large flowers should be protected from rain.

You can propagate geraniums yourself with cuttings. The best times for this are between July and August or at the beginning of the year until March. Here’s the deal:

Geraniums are among the most popular balcony flowers. No wonder, then, that many would like to propagate their geraniums themselves. In this video we show you step by step how to propagate balcony flowers with cuttings.Credit: our store/Alexander Buggisch / Producer Karina Nennstiel

Use healthy shoots that are as strong as possible for the propagation of geraniums. The interface at the bottom must be smooth, otherwise it is susceptible to rot. If in doubt, cut them again with a sharp pair of pruning shears or a cutting knife. It is best to make the cut close to the base of a leaf. The lower leaves are then removed, as are any buds or side shoots. The geranium cuttings are placed about two centimeters deep in prepared pots with special breeding soil. Tip: You can also use the cut off side shoots as cuttings.

The right place for the next three to four weeks is crucial for success: it should be shady, but warm and protected. A foil hood creates conditions similar to those in a greenhouse – but regular ventilation should not be forgotten. In late summer a bright window seat in the house is possible, if it should already cool at night too much. Earth is also important: Low-nutrient breeding soil favours the formation of many fine roots. And when the first new leaves sprout after a few weeks, the reproduction is successful.

The geranium, which originates from South Africa, is not able to withstand the winter temperatures in our country – but you can overwinter geraniums without any problems. To do this, remove the plant from the flower box and remove the loose soil. Make sure, however, that the proportion of fine roots remains as high as possible. Cut all shoots back to a length of about ten centimeters with sharp pruning shears. Two to three knots should remain per side shoot. The leaves of the geranium should be removed as well as possible – this reduces the susceptibility to diseases.tip: If necessary, you can cut cuttings from the removed shoots and grow new plants from them on the bright, warm windowsill.three or four of the geraniums can now be placed in suitable flower pots. The roots are then covered with a mixture of sand and potting soil. The optimal place to spend the winter is a bright place with about five to ten degrees Celsius. During the winter the geranium is kept rather dry and only occasionally poured.

Geraniums as medicinal plants
Among the geraniums there are also medicinal plants: The brew from the roots of the species Pelargonium sidoides and Pelargonium reniforme is used by the native Zulus in Lesotho as a very effective remedy against the disease of the entire respiratory tract, even in chronic infections. The successes were so remarkable that the pharmaceutical industry became aware a few years ago and now sells an alcohol extract from the roots of the plant. She uses the name of the plant from the Zulu language: “Umkaloabo” – which translates as “severe coughing”. In addition, the essential “rose geranium oil”, which plays a role in aromatherapy, is extracted from species such as Pelargonium graveolens.

Diseases and pests
Although geraniums are susceptible to a number of leaf diseases, most of them – in particular bacterial and viral infections – occur mainly in the nursery. The latter cannot be controlled chemically, which is why infected plants must be removed from the greenhouse immediately and disposed of. On the balcony, geraniums occasionally fall ill with geranium rust, which, however, can be easily controlled with fungicides if necessary. Soil fungi such as Pythium cause wilt diseases and occur especially in unsuitable, stagnant substrates. In general, fungal diseases of geraniums on the balcony can be prevented well if the plants are fully sunny and airy, watered only moderately and kept in high-quality balcony potting soil. Especially hanging geraniums sometimes show so-called cork spots on the undersides of the leaves – however, this is not a disease, but tissue scarring due to too abundant water supply at cool temperatures.
More frequent is infestation with insect pests such as aphids, thrips, white flies or spider mites. Remove heavily infested leaves and shoot tips and treat the plants with a biological insecticide if they are more heavily infested. If the geraniums fall ill early in the year, a stronger pruning is recommended before the treatment. By the height of summer, the balcony flowers are well established again and form new flower buds.

Whether fruit, vegetable and ornamental plants in the garden or indoor plants in the house: spider mites can infest and damage many different plants. Here René Wadas, a herbalist, will tell you his tips on how you can effectively fight the arachnids.Credits: Production: Folkert Siemens; Camera: Fabian Primsch; Editing: Dennis Fuhro, Photos: Flora Press/FLPA, GWI

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Don Burke

I am Don Burke, one of the authors at My Garden Guide.  I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.

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