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FAQ – Frequently asked questions about geranium care.

How do I plant geraniums? What varieties of geraniums are there? Are geraniums bee-friendly? Here you will find answers to these and many other common questions about geraniums.

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If a plant sheds its flowers, it usually means it is reacting to great stress. If a geranium loses its flowers in early spring, it was probably kept in conditions like too much darkness for several days on its way from the nursery to the store, or at the store. The shorter the distance from the greenhouse to the point of sale, the less stress for the plants and the better the quality.
Too much (well-intentioned) watering in April and May can also lead to flower drop.

Basic knowledge

Geraniums are easy-care flowers that bloom throughout the bedding and balcony plant season. You can plant them in window boxes, tubs or beds.

Geraniums are among the most popular ornamental plants of all. In Europe, more than 400 million are sold every year.

Often, people use both the name “geranium” and “pelargonium” to refer to the same bedding and balcony plant. “Pelargonium” is its botanical name.

“Geranium” is technically a different plant genus – a hardy perennial. However, the name “geranium” has become commonly used to describe pelargoniums instead.

To avoid confusion, some refer to the hardy perennial plant as “hardy geranium” or “cranesbill geranium”, while the bedding and balcony plant goes simply by the name “geranium”, as well as “pelargonium”.

In total, there are more than 200 species of geraniums. Many of them are only found as wild plants in southern Africa. The following geranium species are most commonly found in the shops:

Upright geraniums (zonal pelargonium) are best suited to flower beds and plant pots. They grow bushy and reach a height of 25 to 40 centimetres.

Trailing geraniums (peltatum pelargonium) can transform balcony boxes or hanging baskets into waterfalls of hanging flowers. They form shoots up to 150 centimetres long.

Interspecific geraniums
can be planted in containers, window boxes or in beds. Interspecific geraniums are special crosses between hanging geraniums and upright geraniums that are particularly weather-resistant and grow extra-vigorously.

Scented geraniums (pelargonium sp.)
are usually grown in pots. They do not have particularly voluminous flowers – usually smaller, delicate buds, but if you touch their leaves they have a scent of lemon, mint, rose or even chocolate. With the flowers and leaves of organically grown scented geraniums, homemade lemonade tastes fantastic and salad gets more pizzazz. Scented geraniums grow bushy.

Regal pelargonium (Pelargonium grandiflorum)
Unlike the others, this variety likes to be planted indoors in a bright spot. They have beautiful, extra-large flowers. You can recognise this variety because the edges of their foliage are slightly serrated. This variety grows upright and compact. Sometimes they are also called “English pelargoniums”.

More information on these and other varieties, such as fancy leaf and butterfly geraniums, can be found here.

Yes, geraniums are very robust and easy to care for. In fact, they thrive and flower almost by themselves. Here we explain what is important when caring for geraniums.

The more light geraniums get, the better they bloom. The ideal location is sunny to semi-shady. Geraniums even tolerate full midday sun.

The classic outdoor geranium varieties flower in the UK from May onwards. Geranium plants that are soon to flower can also be found in the shops earlier. Regal pelargoniums, originally bred as houseplants, can flower as early as March.

Geraniums flower in the UK until October. In a warm, sunny autumn this could be even longer. Exactly how long depends on the temperature and light conditions.

In semi-shady locations, flowering decreases considerably in autumn.

To keep geraniums beautiful for a long time, water and fertilise them regularly, remove faded flowers and position them in a bright, sunny place.

Geraniums are not toxic to humans. The flowers and leaves of scented geraniums can even be eaten, if grown organically (make sure to check the label).

Geraniums are not toxic for dogs or cats, but small mammals such as rabbits, guinea pigs and hamsters should not eat geraniums.

Scented geraniums are said to help repel mosquitoes. Lemon geraniums and pine-scented geraniums in particular exude essential oils that can deter mosquitoes.

Geraniums can usually regenerate after a light frost damage, but only if just the leaves are frostbitten; the stems and roots must still be intact. However, we do not recommend planting geraniums outside when night frost is still expected.

In principle, it is possible to propagate geraniums yourself. You can sow geraniums or take cuttings from existing plants. In practise, however, it does involve an effort.

It is best to take cuttings in July or August. Then you should provide optimal rooting conditions for several weeks. Geraniums must go into winter as small plants.

Geranium seeds are sown in January or February. Geraniums germinate at about 21 degrees Celsius after 10 to 20 days. Then you must separate them and grow them with plenty of light and warmth.

Propagated geraniums usually flower later than purchased plants, because in your home you cannot offer the optimal conditions in terms of temperature and light that they would receive in a professional greenhouse.

Yes, you can get geranium seeds. However, growing them from seed to a full flowering plant takes a lot of effort, and there are not many varieties available.

Geranium seeds should be sown in January or February. Geraniums germinate at around 21 degrees Celsius after 10 to 20 days. Then you should separate them and grow them with plenty of light and warmth.

Home sown geraniums usually flower later than purchased plants, because at home it is not possible to offer the optimal conditions in terms of temperature and light that they would receive in a professional greenhouse.

Single-flowering or semi-double geranium varieties produce pollen and sometimes also nectar, which bees appreciate, especially when food becomes scarce in autumn.

Double flowering varieties produce little food for insects. Nevertheless, a balcony with geraniums can become an insect paradise. All year round, bees can find food in colourful planted boxes if you plant thyme or lavender with geraniums.

Yes, there are geranium varieties that are edible for humans, providing they are not treated with chemical pesticides. Their flowers can be used to decorate salads and the leaves are scented geraniums can flower lemonades, desserts, and other dishes. However, it’s very important that you check the label of the plants you buy, and only eat varieties that state they are edible, which usually means they have been grown organically.

Geraniums do not taste very good to animals. Even the snails are not usually interested.

If dogs and cats nibble on geraniums, it’s no big deal. Geraniums are not poisonous to them.

Small mammals such as rabbits, guinea pigs and hamsters are a different matter. They should not nibble on these summer flowers.

Yes, of course! Geraniums make particularly pretty cut flowers. And it doesn’t matter whether they are the flowers of standing geraniums, hanging geraniums, regal pelargoniums, or the foliage of fancy leaf varieties. Geranium flowers can be combined well with other cut flowers and made into beautiful summer bouquets.

Yes, there are geraniums for indoors. Regal pelargoniums are houseplants that are sold from the beginning of April.

Also, after the first flowering, geraniums can be moved to a sheltered place where they will most likely bloom again.

Geranium plants

Specialist retailers in the UK offer the first geraniums around Easter time. At the end of March/ beginning of April, these are often the so-called regal pelargoniums. They are suitable for bright places in the home.

From mid-April, more and more geraniums are sold for planting outside.

The largest selection is available in May.

It’s impossible to give a blanket price for geraniums in the UK, as it depends on the variety and quality. For example, if you purchase a fully grown plant, it will continue to grow and will flower abundantly in a very short time, but if you purchase a smaller plant or a “plug plant”, you will need to give extra care at first, until they become more established.

The smaller the plant, the more care is needed at home until geraniums flower.

Standing and hanging geraniums

In nurseries and garden centres you can expect to pay around £2 to £3 for a good standard plant, which usually comes in a pot with a diameter of 10.5 centimetres. At the start of the season, they are sometimes on sale for a little less.

Vigorous varieties in 12 cm pots cost a little more.

Solitary geraniums in 13 cm pots or larger will also cost more.

You can sometimes buy small geraniums – known as plug plants – in multipacks online or at discount stores for a lower cost.

For lush balcony boxes, geraniums in 12 cm pots are the best choice, but the standard variety can also work very well, taking a little longer for the gaps in the planting space to grow over.

In containers, premium-quality geraniums in a 13 cm pot or larger will look pretty. However, you do not need to buy large geraniums like this for balcony boxes, because boxes would need to be very voluminous for the root balls to properly set in well.

The reasons for price differences are:

The cultivation of large geraniums consumes more resources than that of small ones. Large geraniums need more space in the greenhouse. They also grow there for longer than the small ones. The big ones also need bigger pots, more soil, more water, more fertiliser, and more work.

Regal Pelargoniums
Regal Pelargoniums are usually found at the same price level as other flowering houseplants.

Good quality geraniums can be recognised by these four quality factors:

  • bushy growth
  • strong shoots
  • plenty of buds
  • well-rooted root ball

As soon as there is no longer a threat of night frost, you can plant geraniums outside. In the UK this can be any time from March to May, depending on where you live.

If you still want to plant them out earlier, here we explain how to protect plants from night frost.

Fresh soil especially for geraniums is best, but general fresh potting soil for balconies and potted plants, or good quality universal potting soil, will also work well.

How to recognise good potting soil:

– smells pleasantly earthy
– is evenly crumbly
– Has additives such as clay and perlite

Unsuitable soil will already smell musty when you open the bag, could show infestation with mould, and fungus gnats might fly up when you reach in. Un-rotted twigs and plastic residues in potting soil are also signs of poor quality.

Fresh potting soil makes care easy. This is for two reasons.

1. Geraniums need a lot of nutrients. With fresh, pre-fertilised potting soil the plants will get off to an optimal start in the season.

2. After a long summer in the balcony box or tub, the old soil will lose much of its structure. It doesn‘t hold water as well as fresh soil. The ratio between coarse and fine pores also changes over time.

The old soil can be composted or used to improve the soil of other flower beds.

The optimal distance between individual plants is 20 centimetres.

Rule of thumb:

40 cm box: 2 geraniums
60 cm box: 3 geraniums
80 to 100 cm box: 4 geraniums
Pot < 20 cm diameter: 1 geranium
Pot > 20 cm diameter: 2 geraniums or more

To give the roots enough space, the plant pot should be 20 centimetres high.
We know that most pots are lower. We advise not buying boxes that are less than 18 centimetres high.

Tips:

  • Use specially designed self-watering planters! They reduce the effort of watering enormously.
  • Buy light colours! Less water evaporates in light-coloured containers than in dark ones because they do not heat up as much in the sun.

A pot with a diameter of 20 to 25 centimetres is ideal for a single geranium.
If you want to plant more geraniums or colourful combinations with other summer flowers, the pots must be larger.

As a rule of thumb, geraniums need a distance of 20 centimetres from the next plant.

Here you can find detailed illustrated planting instructions.
Step 1: Place the root ball of the geranium in a tub of water so that it can soak up more water.
Step 2: Place drainage material in the pot. Fill the container three-quarters full with fresh geranium soil.
Step 3: Plant the geraniums so that the root ball is flush with the surface of the soil. Top up with soil if necessary. Gently press down the soil.
Step 4: Place the container in its desired position. Water.

There are different methods for specially designed self-watering planters.

Important note: Wait until there is no more night frost before planting. Geraniums react to cool temperatures by delaying their development. Temperatures below five degrees will trigger stunted growth, and frost can cost them their lives.

Geraniums can be combined with all summer flowers that like a sunny, warm location.

Possible partners include:

Flowering plants: Phlox (Chaenostoma cordatum), Euphorbia ‘Diamond Frost’, Twinspur (Diacscia), verbena, petunia, and more.

Structural plants: grasses, Frankincense (Boswellia), root vegetables such as sweet potato, Coleus, and more.

Mediterranean herbs: lavender, sage, thyme, and more.

For sunny locations where the heat is less intense, possible partners include impatiens, lobelia, calibrachoa, and heliotrope.

Both upright and hanging geraniums can be planted in window boxes and other containers. They also look beautiful in hanging baskets.
Scented geraniums and regal pelargoniums look best in individual pots, which can be planted in groups.
Geraniums can also be planted in beds. Standing or interspecific geraniums are particularly suitable for this.
Looking for inspiration? You can find it in our design inspiration blog!

Geraniums can transform your balcony and terrace into a sea of flowers. Regal pelargoniums will create an elegant flair in your living room. The leaves of organically grown scented geraniums flavour salads, desserts and lemonades. And decorative leaf geraniums can be used as structural plants in colourful summer combinations.

Geraniums go well with all plants that have similar location requirements to them, so all plants that like it warm and sunny.

Flowering plants: Phlox (Chaenostoma cordatum), Euphorbia ‘Diamond Frost’, Twinspur (Diacscia), verbena, petunia, and more.

Structural plants: grasses, Frankincense (Boswellia), root vegetables such as sweet potato, Coleus, and more.

Mediterranean herbs: lavender, sage, thyme, and more.

For sunny locations where the heat is less intense, possible partners include impatiens, lobelia, calibrachoa, and heliotrope.

In addition, potted plants such as Lantana camara, plumbago or dipladenia can be planted with geraniums.

Yes, upright varieties are particularly suitable, but fancy leaf and scented geraniums are also suitable. Like geraniums in balcony boxes and pots, they all need a sunny location.

You can plant geraniums in flowerbeds or on graves as soon as no more night frosts are expected.
Improve the soil with compost or slow-release fertiliser. Dip the root balls in water before planting so that they are well saturated.
Plant the geraniums deeply, so that the root ball is flush with the soil surface. Do not forget to water them thoroughly!

Yes, geraniums grow very well in specially designed self-watering planters. These containers considerably reduce the effort needed to water plants.

Care for geraniums

Geraniums are robust, so they can cope standing in damp soil for a few days. However, completely soaked soil is not good for them. That’s why it is important to provide good drainage. It is better to water them more often, but in smaller amounts.

In summer, when it is warm and the sun is shining, geraniums need a lot of water. But if you’re not sure whether to water or not, it’s best to keep them a little drier.

With specially designed self-watering planters, plants can help themselves from a water reservoir as needed.

Detailed instructions on how to save completely waterlogged geraniums can be found here.

Geraniums are heavy feeders, so they have a high nutrient requirement. Fertilising should begin after four to six weeks, because by then the first reserves from the fresh potting soil will be used up.

You can fertilise geraniums when you water them once a week by mixing some commercially available liquid fertiliser into the water.

Alternatives include slow-release fertiliser, which is added into the soil and will nourish geraniums for almost the entire season, and fertiliser sticks which last about two to three months.

Click here for detailed instructions on fertilising.

Geraniums are easy to care for. In particular, single-flowering varieties survive rain better than many other summer flowers, as long as their roots are not permanently in water.
It’s recommended to regularly check whether excess water can run off during continuous rain, and to remove broken flowers so that fungal diseases do not spread.

Because nutrients are also washed out with the water run-off, it is worthwhile to fertilise regularly during rainy periods.

This is best done without a knife or scissors. Because the stems are so firm, you can simply grab the faded flower stem at the leaf node and break it off in one swift motion.

You can also use a knife or scissors to cut off the faded geranium flowers close to the leaf node, but you must make sure the blades are clean.

Yes, it is possible to overwinter geraniums.

Cut the plants back to about 15 centimetres before the first night frost and move them to a light, cool place. You will hardly ever need to water them in winter. In spring, repot the plants in fresh soil and place them in a warmer place. With a bit of luck they will sprout and bloom again.

More information about overwintering can be found here.

Geraniums need light, warmth, nutrients and sufficient water to flower abundantly. If you provide a sunny, warm location and fertilise and water regularly, your geraniums will thank you with lush flowers.

Geraniums grow naturally in such a way that they do not need to be cut back during the summer. If you want to overwinter your plants, cut them back to about 15 centimetres before putting them away for the winter.

Geraniums need water only when the soil feels warm and dry. They do not tolerate waterlogging.

At the beginning of the season, watering is not necessary every day, but likewise on very hot summer days, it can be useful to water both in the morning and evening.

Note: Watering may also be necessary even when it is raining, if dense foliage does not allow rain to penetrate to the roots.

It’s best to water in the early morning hours, ideally with water that has been left to go a little stagnant rather than fresh out of the tap. If possible, water directly onto the soil and not on the foliage and flowers.

Scented geraniums like a sunny to semi-shady position in summer.

Water regularly during the growing season and fertilise with half the dose of liquid fertiliser given to other geranium species. Prune shoots regularly for a bushy growth.

Geraniums grow towards the sun. For uniform plants all the way around, turn the pots and tubs 90 degrees every week.

First aid

The first thing to do is to move the geraniums to a warm, bright place where they will not be exposed to any more rain. Then it depends on how wet the geraniums are, and how long this has been the case. Sometimes it can be enough to simply avoid more rain.

If the geraniums have been dripping wet for a long time, we recommend repotting them in fresh potting soil and not watering them at first. The new, drier soil will absorb the water from the wet soil like a sponge until a new equilibrium is reached. Once this has been achieved, start watering again in small doses.

If geraniums are placed on saucers or in a container planter, it is important to ensure that water does not build up in the saucer or planter when it rains.

No. As a rule, this is not a bad thing. Geraniums are robust and need a lot of nutrients to flower profusely. There is no reason to worry if you have fertilised with the correct amount of liquid fertiliser more often, or even with a little more than is recommended in one dose.

However, it can be more critical if liquid fertiliser is diluted much less than it says on the packaging. The higher the concentration of nutrients in the liquid fertiliser, the worse the situation could be. Sometimes highly concentrated fertiliser can corrode the roots. If the mistake is noticed quickly, it is possible to rinse the root ball immediately with plenty of water.

Geranium rust is a fungal disease that is characterised by ring-shaped circles on the underside of the leaves and yellowish spots on the top of the leaves. It only spreads when it is warm and there is water dripping on the leaves at the same time.
Remove infested leaves immediately and dispose of them in the household waste. To prevent the rust from returning, place the plants at a greater distance from each other in a better ventilated place and make sure that as little water as possible gets onto the foliage when watering.

Yellow leaves on geraniums are often a sign of nutrient deficiency, so fertilising can help. Check out our tips on fertilising.

Also, early in the season, when temperatures are low and fluctuate greatly, cold-induced chlorosis is common on young leaves which can cause yellowing.
This can be avoided by protecting plants from temperatures below 8 degrees.

A grey coating on plants is usually due to a fungal disease called botrytis. It makes the affected plant tissue turn mushy. Botrytis, or grey mould, spreads easily when plants are very dense, humidity is high and it rains for several days in a row during warm periods.

First aid: Plant parts infected with botrytis must be removed as soon as possible.

You can prevent it by regularly removing faded flowers and plucking off dead leaves.

If soil is dry and dusty because it has not been watered for a long time, your geraniums are probably drooping because they have used up most of their stored water, and no longer have enough. If so, replenish their water supply as soon as possible!

Conversely, if soil is moist and geraniums are still drooping, the plants are probably very waterlogged which means the roots are already starting to rot. They might recover when the water balance is restored.

First aid: Don’t water any more, and let the soil dry out – or repot the plants straight away in new potting soil.

Very rarely, a fungal disease may have taken root that prevents the plants from absorbing water. In this case, geraniums can usually no longer be saved.

In general, geraniums are robust and undemanding. If they do not flower, it’s worth checking that they are in the correct environment: ideally a warm and sunny, at most semi-shady location, with sufficient water and regular fertilisation.
If geraniums do not flower early in the season – in the UK around April or May – they probably haven’t had enough light yet. This is especially likely with very small plants, such as plug plants that are available in multipacks.

Temperatures below 5 degrees can also delay development.
So don’t plant geraniums outside too early and always buy the strongest ones you can find.

Tips on how to recognise good quality geraniums can be found here.

Red leaves can have various causes in geraniums:

1. A big difference between temperatures during the day and at night.
2. Too much water
3. Too little water
4. Lack of the nutrient phosphorus
5. Soil with a low pH value
6. Geranium rust (fungal disease)
7. It could be a special foliage ornamental variety with red leaves.

Geraniums should be kept cool over winter, for example in a frost-free garage or in a similarly cool place indoors.
To overwinter, bring the plants indoors before the first night frost and cut them back to about 15 centimetres.

During their winter dormancy they need almost no water. In spring, repot the plants in fresh soil and place them in a warmer spot. With a bit of luck they will sprout and bloom again. More information on overwintering can be found here.

If the buds on your geranium plants dry out early, it’s a sign something is wrong with the conditions in their environment. The good news is that if the situation improves, new flowers will quickly appear.

These are the three most common causes of brown flowers:

1. Lack of hardening off, which means the process of gradually exposing plants to climate and temperatures.
2. Lack of light due to a location that is too shady.
3. Too much water at the start of the season, when there were limited roots.

If a plant sheds its flowers, it usually means it is reacting to great stress. If a geranium loses its flowers in early spring, it was probably kept in conditions like too much darkness for several days on its way from the nursery to the store, or at the store. The shorter the distance from the greenhouse to the point of sale, the less stress for the plants and the better the quality.

Too much (well-intentioned) watering in April and May can also lead to flower drop.

Geraniums are robust and easy to care for. Under normal circumstances, vigorous plants do not suffer from pests. Even slugs and snails do not normally bother geraniums. If pests do arrive on your geraniums, it’s probably a sign that they were weakened beforehand.

– Spider mite
Damage: silvery sheen of the leaves
Control: pruning, possibly use of biological control (beneficial insects such as predatory mites)

– Thrips
Damage: silvery sheen of the leaves
Control: pruning, blue tablets

– Whitefly
Damage: white flies and sticky coating on the leaves
Control: pruning, yellow boards

– Aphid
Pest symptoms: crippled leaves with yellow spots, colonies of black aphids on the stems and undersides of the leaves
Control: pruning, insecticides (biological based) against sucking insects

Warts on the underside of leaves is called corking. They develop when temperatures are cool and the substrate is too wet. Corking will not go away, but it will not harm the plant.

First aid: Place plants in a brighter place that is as warm as possible. Water as needed.

Yellowish spots on the top of the leaf in combination with brown circles on the underside of the leaf indicate a fungal disease called Pelargonium rust.
Pelargonium rust spreads at warm temperatures and high humidity. Usually the plant as a whole will regenerate, and infested leaves will not.

First aid: Remove infested leaves, and dispose of them in household waste. Place plants in a well-ventilated place with plenty of space between them. If possible, do not pour water on the leaves when watering.

These are fungus gnats. They appear when the potting soil is too wet and the weather is warm and humid. Fungus gnat larvae feeds on the roots.

First aid: Let the soil dry out very well, and in future, water only when the soil surface is dry. You can also remove them with sticky yellow insect traps, or by introducing beneficial insects (biological control), which can sometimes be found at garden centres or available to order online.