Geraniums, also known as pelargoniums, are the no. 1 flowers for balconies. You can read all about caring for and cultivating these colorful continuous bloomers here.
Origin and Growth
Geraniums, actually correctly known as pelargoniums, originate from South Africa - there are 250 wild species of Geranium in South Africa alone. Many varieties are located around the costal region of Cape Town in particular. These easy-care and heat-resistant plants can also be found in other countries: The species Pelargonium australe and Pelargonium indoroum are found in Australia and New Zealand, Pelargonium endlicherianum grows in Anatolia, and the geranium species Pelargonium quercetorum can be found in Iraq and Iran.
There is no historical record as to exactly when or how the first geraniums arrived in Europe. Around the 17th century, tradespeople are thought to have begun importing species of pelargoniums. They were incorrectly referred to as geraniums at that time and therefore were given the colloquial name geranium. They were first assigned to the genus pelargonium in 1789. In their native home and also here, the variety can hardly be measured - and every year numerous new varieties are added. Geraniums belong to the storkbill family (Geraniaceae) and are initially differentiated according to three types: Ivy geraniums (Pelargonium peltatum) and zonal geraniums (Pelargonium zonale), which have generally been bred as long-flowering and resistant varieties with large flowers. There are also scented pelargoniums, which are frequently used in the extraction of scented oils.
Geraniums are one of the most popular balcony and garden flowers in this country as they do not require a lot of care and flower all summer long. Geraniums flower in the widest variety of colors: From white to pink, red and purple: all the colors are possible. The flowers on umbels are often two-tone or patterned with stripes or dark speckles. The variety ‘Mosaic Purple’, for example, has beautiful striped and speckled petals. Geraniums require cooler nights in order to continue flowering until the frost - this applies in particular for Regal Geraniums.
Pelargoniums have bushy growth and strong shoots. Some varieties have beautiful, patterned foliage. Upright geraniums are considered evergreen half-bushes and grow 9.84 to 15.75 inches tall. Ivy geraniums generally grow up to 11.81 inches tall, however they can form long, overhanging shoots over 59 inches long. Their stalks are slightly hairy and start to wooden from the bottom over time.
Caution, poisonous! Geraniums are not poisonous to people. Animals such as hares, rabbits, guinea pigs, and hamsters, however, should not be allowed near these plants. They are poisonous for these animals and cause skin damage.
The Various Geranium Groups
Geraniums are unbelievably multi-layered and offer lots of variety in terms of growth shape, leaves, and flowers. They can be subdivided into six groups, which in turn have lots of different varieties.
With their long, cascading flowers, ivy geraniums (Pelargonium peltatum) are a classic in elegant window boxes. Robust, single flowering varieties such as those from the ‘Cascade’ series or the well-known pink ‘Ville de Paris’ are particularly popular. These grow vigorously. On the other hand, single and double-flowered varieties have more compact growth. A covered location is more favorable for these as their flowers become sticky in long periods of rain.
It’s not the flowers that are the main event with these, but their leaves! Scented geraniums are available in countless variants and each one is a surprise with a special aroma, for example, 'Chocolate Peppermint' (chocolate), 'Queen of Lemons' (lemon), 'Purple Unique' (wine gums), 'Bourbon' (rose), 'Lady Plymouth' (peppermint), 'Orsett' (pepper-citrus) - fantastic for adding aroma to meals and beverages! Some scented geraniums even help to keep away mosquitos with their spicy aroma.
Regal geraniums (Pelargonium x grandiflorum) were originally houseplants. But they have also been enriching balcony plant arrangements for some time with their durable, hardy new breeds. The special thing about these is their often large, beautifully marked flowers. The grow upright and compact, typically with toothed leaf margins. ‘Clarion Violet’, for example, flowers pink with a dark eye, ‘Velvet Red’ has velvety purple flowers. Regal geraniums enjoy a sheltered location.
Zonal geraniums (Pelargonium x hortorum) delight with a wide range of varieties. Most adorn themselves with single and double flower balls in white, pink, purple, red, orange, and pink tones, often with intensely colored, vibrant eyes such as ‘Grandeur Light Pink Splash’. Stellar pelargoniums are new. They stand out with their star-shaped flowers (‘Stellar’ and ‘Graffiti’ varieties)
Zonal geraniums (Pelargonium x hortorum) delight with a wide range of varieties. Most adorn themselves with single and double flower balls in white, pink, purple, red, orange, and pink tones, often with intensely colored, vibrant eyes such as ‘Grandeur Light Pink Splash’. Stellar pelargoniums are new. They stand out with their star-shaped flowers (‘Stellar’ and ‘Graffiti’ varieties).
Ornamental Foliage Geraniums
These are a sub-group of the zonal geraniums with colorful, beautifully marked foliage. Zonal geraniums (Pelargonium x hortorum) have a long tradition, they were already nurtured and cultivated in England in the 18th century. In addition to their beautiful leaves they have pretty, decorative flowers. The varieties of the ‘Pelgardini’ series, for example, are some of the new breeds.
Pelargoniums are most popular as balcony plants with their beautiful flower carpets. The numerous expressive flowers create an huge impression from a distance. Window boxes elegantly adorned with geraniums can be found on large farm houses. However, the pretty balcony flowers are also increasingly being planted in window boxes in cities.
And the easy-care classic also looks great in garden seating areas and on the patio in small and large containers, as hanging baskets and standards. Stellar geraniums, for example, prefer to be placed in planters. With their decorative flowers that stand tall above the foliage, these are a truly decorative addition for seating areas on the patio or balcony. ‘Angeleyes’ geraniums are also suitable for plant containers. They look particularly good if they are used in small pots as table decorations. You can also use regal geraniums as houseplants.
Their impact from a distance is highlighted in particular with the correct planting partner. Almost all other hanging or upright balcony flowers work with geraniums. The simplest combination for window boxes are two geraniums of different colors - pink colored and crimson varieties create a fantastic harmony, for example. If you want more variety, color coordinated verbena, frankincense, waterhyssop (Bacopa) or blue Nemesia are also suitable companions. There are no limits to the creativity you can exercise with the composition. It’s best to ensure that the plant partners have similar properties. This makes caring for them later easier for you. Combining with herbs in a Mediterranean style is an excellent eye-catcher. Similar to geraniums, herbs love warm temperatures and lots of sun. The gray-green of sage and rosemary or the blue tones of flowering lavender make a wonderful addition. Argyranthemum (Argyranthemum), zonal geraniums and white, elegant overhanging Achillea ptarmica ’Gipsy White’ make a great trio. You can find more design ideas with geraniums here.
Planting and Care
Large pots or window boxes (7.87 x 39.37 inches) are ideal for geraniums. You can put around five plants in these. The boxes should be at least 7.09 inches deep to ensure a good fertilizer and water supply. Planters for pelargoniums should have water drainage holes or good drainage, as this sun-worshipper doesn’t like wet feet at all.
Geraniums can be repotted in fresh soil from the end of February and placed to grow in a bright, cool window space. In cold regions the geraniums should only be placed in good balcony potting or geranium soil after the frosts have finished - around the middle of May. Several cuttings can be used for this. If you want to buy new geraniums, avoid going for seeds. This type of cultivation is laborious and slow. Instead, we recommend young plants - these are available from the spring.
Pelargoniums need a lot of nutrients in their growth phase. So you should already check when positioning them that the potting soil is well fertilized. You should continue to fertilize at regular intervals three to four weeks after planting.
Geraniums need a lot of water, but they shouldn’t be kept constantly wet. So you should only water them when the soil has dried out. Waterlogging leads to large, brittle leaves and, in ivy geraniums, corking on the underside of the leaves.
In order to prevent weeks with high levels of precipitation leading to rot or mold forming on deadheads they should be cleaned regularly. This also strengthens flower reformation. The most easy-care geraniums are those in the Cascade group. In addition to their reliable flowers and great long-distance impact, these varieties are also self-cleaning - they do not require pruning.
Perlagoniums require a nutrient-rich soil and are suitable for locations in full sunlight to semi-shade. The rule applies here: The more hours of sunlight, the more flowers will form. A gentle breeze doesn’t do the plants any harm, however if they are in wind that is too strong, the shoots break off easily. Pelargonium species with large flowers should be sheltered from the rain.
You can propagate geraniums yourself using cuttings. The best times for this are between July and August or at the start of the year in March. Here’s how:
Use the healthiest and strongest shoots for propagating geraniums. The cutting point at the bottom end must be smooth or it will be susceptible to rot. If in doubt, cut once more with sharp secateurs or a knife for cuttings. The cut is best made just underneath a leaf base. Then remove the lower leaves and any buds or side shoots. The geranium cuttings are pushed about 0.79 inches deep into a small prepared pot with special potting soil. Then push in well and water carefully.
Tip: The cut off side shoots can also be used as cuttings.
The correct place over the next three to four weeks is crucial for success: it should be shady, but also warm and sheltered. You can create greenhouse-like conditions with a film cover - but don’t forget to ventilate regularly. A bright window space in the house is possible in late summer, should the nights already become considerably cooler. The soil is also important: Low-nutrient potting soil is favorable for the formation of many fine roots. If the first new little leaves sprout after a few weeks then the propagation is successful.
The South African native pelargonium is not used to wintery temperatures - however you can easily overwinter geraniums. For this, remove the plant from the flower box and remove the loose earth. But be careful to ensure that it retains as many fine roots as possible. Then cut back all the shoots with sharp secateurs to a length of about 3.94 inches. There should be two to three nodes left on each side shoot. The geranium leaves should be removed as far as possible - this reduces the susceptibility for disease.
Tip: You can take cuttings from the removed shoot parts if needed and grow new plants from these on a bright, warm window sill.
The pelargoniums can now be planted in groups of three or four in suitable flower pots. Then cover the roots with a mixture of sand and potting soil. The best overwintering location is a bright place at about 41 to 50 degrees Fahrenheit. Geraniums should be kept drier during the winter and only watered occasionally.
Geraniums as medicinal plants
There are also medicinal plants among the pelargoniums: A brew made from the roots of the species Pelargonium sidoides and Pelargonium reniforme is used by Zulus native to Lesotho to make an extremely effective remedy against all respiratory diseases, even in chronic infections. The success was so astounding that the pharmaceutical industry became aware of it a few years ago and no markets an alcohol extract from the roots of the plant. This is also where the plant gets its name in the Zulu language: "Umkaloabo" – which translates to mean “bad cough”. The ethereal “rose geranium oil”, which plays a role in aromatherapy, is also extracted from the species Pelargonium graveolens.
Diseases and Pests
Geraniums are susceptible to a number of leaf diseases - however, most of these - in particular the infections caused by bacteria and viruses - occur mainly during cultivation in garden centers. The latter cannot be combatted with chemicals, which is why infected plants must be immediately removed from the greenhouse and disposed of. Geraniums on the balcony occasionally suffer from geranium rust, but this can be combatted with fungicides if necessary. Soil fungi such as Pythium cause withering diseases and mainly occur in unsuitable, waterlogged substrates. Fungal diseases can generally be easily prevented in geraniums on the balcony if the plants are in full sunlight and fresh air, only moderately watered and kept in high-quality balcony potting soil. Ivy geraniums in particular sometimes show so-called cork flecks on the undersides of leaves - however, this is not a disease but tissue scarring due to excess watering in cool temperatures.
Infestations from harmful insects such as aphids, thrips, whitefly or spider mites are more common. Remove heavily infested leaves and shoot tips and treat serious plant infestations with a biological insecticide. If geraniums become sick early in the year, heavy pruning is recommended before treatment. The balcony flowers will shoot well again until high summer and form new flower buds.
Frequently Asked Questions
When can I plant geraniums?
Geraniums can be planted from the end of February in fresh soil and in grown in a cool and bright place by the window. In colder regions, wait until after the last frost before planting.
How often should I water geraniums?
Although geraniums do need a lot of water, the soil should be allowed to dry out between watering as geraniums are very sensitive to waterlogging.
What colors do geraniums come in?
Whether in white, pink, red or violet: The popular balcony and garden plants flower in the widest variety of colors. Today, there are also lots of multi-colored varieties available with flecked or striped petals.
How frost-sensitive are geraniums?
As geraniums originate from South Africa they are unfortunately very sensitive to frost. However, you can easily overwinter geraniums.
When should geraniums be overwintered?
Geraniums do flower tirelessly into the fall, however they should be moved to their winter residence before the first frost.