Geranium SOS: the winning formula for healthy geraniums and a carefree summer.

flowering retreat, a place to unwind. That would be something! If it weren’t for the fear that only aphids, snails and whiteflies would be happy about the plants on the balcony.

But the solution is only a purchase away:

If you want a carefree summer, you need geraniums. They won’t cause any trouble!

Why geraniums are the best choice for a carefree summer; what care this resilient flowering beauty needs; and what to do if problems do arise – the experts at Pelargonium for Europe (PfE) have all the answers

Why plant geraniums?


Geraniums rarely suffer from pests and are also surprisingly easy to care for.

They show their strength when other summer flowers falter:

Hot and dry – that’s just their thing. What’s more, the sunnier and hotter the summer, the better geraniums thrive. For months, bloom after bloom appears – from the day it’s planted until the first frost. Because it’s so robust, this floral showstopper simply outgrows many a problem. Even the nicest snail weather doesn’t dampen the joy of geraniums because snails shun the fleshy shoots and leaves.

How to care for geraniums to keep them healthy


Geraniums need a sunny to semi-shady spot. These easy-care South African natives also tolerate midday sun very well. Geraniums bloom at their best when they’re watered regularly and the soil doesn’t dry out completely, but doesn’t get soggy either. As they grow, these summer beauties need a lot of nutrients, which can be easily provided by liquid or slow-release fertiliser for flowering plants. You can avoid fungal diseases if you remove faded flowers, especially after heavy rain. A welcome side effect of doing this is that the geranium will bloom even more abundantly than it already did.

Poor soil and dirty pots can introduce pests and diseases. Clean used containers quickly with a scrubbing brush before planting.

A loose, structurally stable growing medium forms the basis for healthy growth; so when it comes to compost, an investment in quality pays off hugely.

Geraniums are robust by nature but if things happen that shouldn’t, here are five SOS tips for the most common problems. They can all be solved without the use of chemicals.

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

Oedema appears as cork-like warts on the underside of the leaf. These can develop when temperatures are cool and the supply of water is too high. The geraniums try to get rid of the excess water. This causes their stomata (cell structures in the leaf surface that regulate evaporation) to rupture which damages the tissue. The corky spots are the scarring that occurs as it heals.

Prognosis: Not pretty, but not dangerous.

First aid: Place plants in a brighter place and as warm as possible, water as required


SOS: What to do about yellow leaves

There are many causes for pale leaves. Lack of light is a factor, as is nutrient deficiency. Especially at the beginning of the season, cold-induced chlorosis (the scientific term for yellowing leaves) occurs repeatedly. It occurs at temperatures below 8°C or when temperatures still fluctuate strongly in early summer.

Prognosis: It grows out.

First aid: Protect plants from excessively cold temperatures and/or keep warm with a garden fleece. Fertilise in case of nutrient deficiency. Cleaning off can also be helpful.

SOS: What to do about spots on the foliage


If yellowish spots appear on the tops of the leaves and at the same time ring-shaped, brown circles appear on the underside of the leaves, the plant has caught pelargonium rust. Pelargonium rust is a fungal disease. It can occur in summer temperatures and at the same time in high humidity. Pelargonium rust spreads exclusively via water splashing onto the leaves.

Prognosis: The plant will regenerate, the affected leaves will not.

First aid: Remove affected leaves immediately and dispose of them in the household waste. Move the plants to a better ventilated place with more space between them. When watering, make sure very little water gets onto the leaves.

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

Wenn If the soil is moist and the foliage still wilts, the plants have probably been overwatered. If there is too much moisture, the larger pores of the potting compost will become clogged with water. This disturbs the vital exchange of oxygen and carbon dioxide at the root tips and promotes rot.

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

First aid: Do not water any more. Allow the soil to dry. If the potting compost was not the best in the first place, repotting can make the best of a bad job.

SOS: What to do about poor growth and black gnats?

Black gnats that buzz around near the potting compost are usually fungus gnats (sciarid flies). It is their larvae that cause problems. They nibble at the roots and develop very well when the soil is wet and the climate is warm and humid.

Prognosis: Everything should be fine if the roots are not yet damaged.

First aid: Let the soil dry out completely to give the roots time to recover. In addition, it helps to remove flowers and buds so the plant can put its remaining energy into regenerating the roots and leaves. In future, water only when the surface is dry. You can also put up sticky yellow attractant panels to attract the gnats. Biological control insects, such as pathogenic nematode worms or the fungus gnat mite, Hypoaspis miles, help against severe infestations.