- Geranium care: 7 golden rules for maximum flower power -

Geranium care: 7 golden rules for maximum flower power

Everything feels better with geraniums. Your mood, your day, simply everything. Especially in summer, when lush flowering balconies lure us outside. But you might be thinking that caring for geraniums is a lot of work. Our response? It doesn't have to be.

Everything feels better with geraniums. Your mood, your day, simply everything. Especially in summer, when lush flowering balconies lure us outside. But you might be thinking that caring for geraniums is a lot of work. Our response? It doesn’t have to be.

Easy-care & colourful: why geraniums make the ideal balcony flower

If you opt for geraniums, you don’t need green fingers. You don’t even have to invest a lot of time in caring for them and you can still enjoy the summer surrounded by a sea of flowers.

  • Geraniums (botanically they belong to the genus Pelargonium) are an absolute classic among flowering bedding and balcony plants, yet they’re also totally on-trend.
  • As perennial favourites in balcony boxes, hanging baskets and containers, they look impressive in sunny to semi-shady locations, thanks to their abundance of blooms, long flowering period and unbeatable variety of colours and shapes.
  • There are countless varieties with single, semi-double and double flowers. Some grow upright, others trailing – there’s something low-maintenance for everyone. 
  • These popular balcony plants are very hardy. They can withstand periods of heat as well as temporary drought.   
  • Infestation by pests and diseases is very rare.   

In short, geraniums are surprisingly hardy and easy to care for. This makes them the ideal plant for people who like to surround themselves with lush blooms, even if they don’t (yet) have green fingers or can only invest a little time in plant care. This is precisely why geraniums are one of the most popular summer flowers. 

Simply follow these rules for siting, planting, watering, fertilising, pruning and overwintering geraniums – Mother Nature will take care of the rest and you’ll have time to chill out on the balcony. 

Rule 1: The ideal location for geraniums is warm and sunny

Geraniums originate in South Africa. That’s why they like it warm and bright. If you give them a sunny spot, they will thank you with lots of flowers. No need to worry about blazing midday sun, as geraniums can even tolerate this intense heat. 

Is your balcony not so spoilt by the sun? Geraniums also grow very well in a bright, semi-shaded location. Only deep shade doesn’t suit them. For a north-facing balcony, it’s best to look for other floral summer companions. 


What ‘sunny’, ‘semi-shady’ and ‘shady’ really mean

In a sunny location, the sun beats down from the sky all day long and there is no shade. It gets very hot very quickly in summer.   

If your balcony receives diffuse light all day or is shaded by trees, houses, a privacy screen, etc. for no more than four hours, you are dealing with a semi-shady location.   

It is always shady on the north side of buildings, under dark eaves and in other places where the sun never reaches directly.    

Rule 2: Balcony geranium season should only start after the last frost

Don’t put geraniums out too early in spring. The traditional recommendation is to wait until after the last frost, around mid-May. But things are evolving with climate change. In a warm location, the right time to plant may well be a few days earlier.   

Still, it’s important not to put geraniums outside permanently until after the last night frost. These otherwise hardy plants react to temperatures below 5°C with a pause in growth and frost can kill them.

Have you bought geraniums much earlier and already planted them? Then find out here how to protect geraniums from frost in an emergency.   

Rule 3: Plant with plenty of space in good quality compost

When planting, buy the best compost you can, and use reasonably deep containers. This costs a little more than cheap potting mix and smaller balcony boxes or pots, but the investment is worth it. After all, you are laying the foundations for the whole summer when you plant. 

Special geranium compost perfectly meets the needs of this classic balcony plant and retains moisture so well that you need to water less often. Other loose, structurally stable growing media also form a good basis for healthy growth. Use peat-free compost if climate protection is important to you.   

Speaking of growth: geraniums grow quickly and vigorously. For young plants to develop well, they need space – about 20cm between them and their neighbour. 


What quantities do I need?

Extra: Tips for planting trailing geraniums

  • Cut open the basket 
  • Hanging geraniums are often sold with a basket over the stems. Simply cut it open with secateurs and don’t try to prise the plants out. 
  • Set at an angle 
  • Place the root ball at a slight angle in the soil. This will guide your trailing geraniums in the direction you want them to grow. 
  • Keep lower leaves out of the soil

Your geraniums’ leaves must not be buried in the compost. They could rot and might stop your summer flowers growing properly.

A cosy balcony furnished with a round wooden table and matching chairs. Lush geraniums in bright colours adorn the railings and offer a view of the picturesque façade of the buildings opposite. A teapot and cups on the table encourage you to take a relaxing break.

Rule 4: Water less rather than more

To bloom abundantly and continuously, geraniums need watering regularly. Use your finger to find out whether you need to give them a drink. 

If the soil feels dry and warm to a depth of 2cm, your plants need more water. 

Watering geraniums correctly for beginners

😎 Your geraniums don’t need water if the soil feels cool and moist.  
💡 The ideal time to water is when the soil is warm and dry to the touch.   
🐎 Water urgently when the soil comes away from the edge of the pot.
🌅 Water the soil in between the plants, preferably in the morning or evening
💦 Allow half a litre of water per plant
🫠 Drain off any excess water 

Why you can't rely on sight alone

Unlike other balcony flowers, it’s hard to tell when geraniums are too dry, as they store liquid in their fleshy leaves and thick-walled stems. This means occasional dryness doesn’t bother them. They will grow and flower better, however, if you meet their water needs promptly. 

Not sure whether you should reach for the watering can? Then keep the soil drier, rather than too moist.   

This information will help you get by. We answer all your questions about watering geraniums in this post: What you need to know about watering geraniums.    

Rule 5: Fertilise geraniums for beautiful flowers

Let’s be clear: Fertilising is essential for healthy dream geraniums. They won’t die without it, but they won’t grow and bloom the way you want them to. 

If you don’t want to worry about feeding your plants in summer, sprinkle slow-release fertiliser into the soil when you plant them. Alternatively, mix liquid geranium fertiliser into the water every week. 

Did you forget the slow-release fertiliser but don’t want to use a liquid version? Then you can insert fertiliser sticks into the soil at any time. They release their nutrients for up to three months. Fertilising can be that easy! 

A pot of blooming, pink geraniums stands in the foreground, its vibrant colours standing out clearly against the dark background. Partially visible in the background is a modern chair placed next to a small side table. The composition conveys a modern yet cosy flair.

3 ways to fertilise geraniums

1. Mix slow-release fertiliser into the soil when planting
2. Use liquid fertiliser weekly when watering
3. Insert fertiliser sticks into the soil once a quarter 

Interesting facts about care

Interspecific, upright and trailing geraniums need a lot of nutrients due to their vigorous growth and abundant flowering. Scented geraniums are less demanding and only need half as much fertiliser.   


Rule 6: Deadhead to encourage new flowers

When deadheading, break off any flowers past their prime.
By removing faded blooms, you encourage the plants to produce new, colourful ones.   

How to deadhead

To remove the flowers, grab the flower stalk by the leaf node and bend it over with a quick jerk. Using your fingers is enough. Thanks to the crisp stems, you don’t need sharp secateurs to remove faded flowers.   

Pruning is easier shortly after watering or a downpour when the stems are full of water.   

Upright geraniums especially benefit from deadheading and for trailing geraniums it’s more important for semi-double and double varieties than for single-flowering ones.   

There are ‘self-cleaning’ varieties for those who don’t want to deadhead. Their withered flowers fall off all by themselves. A professional grower will be happy to advise you on how to get the most out of your flowering geraniums. 

When you deadhead, remove any withered leaves too. This will keep your geraniums healthy.   

Instant deco like a pro

For that special occasion, cut geranium flowers are also fabulous for making a quick arrangement that looks like it was made by a florist. 

Rule 7: SOS tips for problems

SOS: What to do with warts on the underside of leaves

Cork spots looks like warts on the underside of the leaves. They can occur in cool weather and with too much water. The geraniums try to get rid of the excess water. Their stomata (cell structures in the leaf surfaces that regulate evaporation) tear open wider than they should. 

This damages the tissue. The cork spots are the scars that form on the affected leaves as they heal. 

Prognosis: Cork spots on geraniums aren’t pretty, but they’re harmless. 

First aid: Place plants in as sunny and warm a location as possible and water when necessary. There’s no need to remove the affected leaves. 

SOS: What to do about yellow leaves

When a plant turns chlorotic, the leaf tissue loses its green colour because it isn’t producing enough chlorophyll. There are many causes of discoloured leaves. A lack of light is one, as is a lack of nutrients. At the beginning of the growing season in particular, cold chlorosis can occur repeatedly. It happens at temperatures below 8°C or when the mercury still fluctuates considerably in early summer.   

Prognosis: It will grow out, most quickly in dry, warm weather.   

First aid: Protect plants from cool temperatures and continuous rain and/or keep them warm with a garden fleece in a sheltered location. Fertilise if there is a lack of nutrients, which can be quickly washed out of compost in wet weather. Removing any dead sections will help your plants regenerate.    

SOS: What to do about spots on the foliage

If yellowish spots appear on the upper side of the leaves and brown rings become visible on the underside of the leaves at the same time, your plant has caught pelargonium rust.   

Pelargonium rust is a fungal disease. It can occur occasionally in summer temperatures and high humidity. Pelargonium rust spreads via water droplets on the leaves, so it only occurs when the foliage is wet.   

Prognosis: The plant will recover, but the affected leaf will not. 

First aid: Remove affected leaves immediately and dispose of them in household waste. Move your plants to a better ventilated location with more space between them. When watering, ensure that as little liquid as possible gets onto the leaves. 

SOS: What to do if your plants are growing poorly and have black midges?

Black midges buzzing around near the soil are usually fungus gnats. Their larvae cause problems. They nibble on the roots and flourish when waterlogged soil and a warm, humid climate come together. 

Prognosis: Everything will be fine if the roots aren’t yet damaged. 

First aid: Allow the soil to dry out thoroughly to give the roots time to recover. It also helps to remove any flowers and buds so the plant can put its remaining energy into regenerating the roots and leaves. In future, only water when the soil surface is dry. Set up sticky yellow card insect traps. Biological control insects can help against severe infestations. The microscopic nematodes Steinernema feltiae penetrate the fungus gnat larvae and feed on them, killing them.   

SOS: What to do if your plant wilts even though the soil is moist?

If the soil is moist and the foliage is still wilting, your plant has probably been overwatered. If there is too much moisture, the large pores in the compost become saturated with water. This disrupts the vital exchange of oxygen and carbon dioxide at the root tips and encourages rotting. 

Prognosis: Geraniums usually recover when the water balance is restored. 

First aid: Don’t water anymore. Allow the soil to dry out before watering again. If the compost was not top quality in the first place, repotting in fresh compost can save whatever can be saved. 

Bonus: Overwintering - Why geraniums deserve a second chance

As we mentioned at the start: geraniums don’t like frost. That’s why most amateur gardeners treat them as annual summer flowers. Everybody’s darling for one season and then they’re gone. Yet geraniums are actually perennials that can last for several years. 

If you want to give overwintering a try, before the first night frost, cut your plants back to around 15cm and place them in a pot in a cool, bright room (5-10°C) for the colder months. In winter, these plants, which flower so abundantly in summer, need almost no water as their metabolism is reduced. 

In spring, repot your overwintered geraniums in fresh compost. Do this in containers twice the size of the root ball. Then place them in a warmer spot (room temperature). With a bit of luck, your plants will sprout again and produce new, colourful flowers. After the last frost, move your plants back outside. 


Instructions for overwintering geraniums:

  • Cut back before the first frost
  • Place in a bright, cool room (5-10°C)
  • Water as little as possible in winter
  • Repot in March, water and keep in a warmer place (room temperature)
  • Move outdoors after the last frost 

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