Geraniums impress with their colorful flowers. With the right care - the right cutting, watering and fertilizing - diseases can be avoided.
Pelargoniums (Pelargonium, also geraniums) belong to the cranesbill family (Geraniaceae). Most of the approximately 250 game species are native to South Africa, but came to Europe in the early 16th century. At that time, they were erroneously classified in the genus Geranium. However, Pelargonium and Geranium differ in flower structure. Pelargoniums owe their popular name as geraniums to this taxonomic faux pas. Since its successful entry into Europe, the geranium as such has not only been established linguistically, but through intensive breeding new color variants are constantly emerging. The flowers of the numerous varieties shine from May until the first frost in an attractive spectrum of colors from white to red to violet. But it is not only their appearance that makes them one of the most popular bedding and balcony plants in Germany. They are also less susceptible to diseases and pests, can also dry out and can be multiplied and overwintered very easily. In summer you can see the colorful variety of their carpets of flowers on almost every balcony. But in order for your own balcony to shine in a sea of flowers like the balconies of the typical Upper Bavarian wooden huts, the care has to be right.
Geraniums are not exactly high-maintenance. But in order for beautiful flowers to appear in large numbers on strong shoots, your geranium needs a lot of fuel in the form of water and regular fertilization. Using scissors also strengthens he althy growth and is essential before the South African beauties overwinter. In this article you will learn everything about watering, fertilizing, cutting and overwintering geraniums so that you can know that your balcony favorites are completely happy.
Watering geraniums correctly
Not only do geraniums gobble up nutrients, they also need a lot of water. Although geraniums can also dry out without being damaged, they only bloom particularly luxuriantly if they are regularly watered with room-temperature rainwater.However, care must be taken that the plants are not constantly wet. Therefore: It is better to water vigorously once than frequently with small amounts of water. Only water again when the soil has dried and avoid waterlogging.
Watering geraniums summary:
- Water regularly and vigorously
- Avoid waterlogging
Tip: If your geraniums look limp and wilted despite sufficient watering, this may be due to root damage caused by waterlogging.
Fertilize geraniums properly
Geraniums are heavy feeders. This, combined with the frequent cultivation in pots, means that you will not be able to avoid fertilization. You should fertilize the hungry plants from planting into October. You can use the following fertilizers for geraniums:
- Compost and horn shavings
- Special flower fertilizers
- Mineral fertilizers such as blue grain
When planting, you can use a long-term fertilizer such as compost and horn shavings. As a rule, three liters of compost per square meter and a handful of horn shavings are worked into the potting soil. After that, you do not need to fertilize for three to four weeks. Instead of compost or horn shavings, you can also incorporate a mostly organic slow-release fertilizer into the soil.
When choosing fertilizer, you should make sure that the nitrogen content (recognizable by the "N" of the NPK ratio) should be larger. The phosphate content (P), on the other hand, should be the smallest. Our Plantura organic flower fertilizer is the ideal choice. It consists mainly of organic components. In this way, you not only protect the environment, it also supports the microorganisms in the soil, because the nutrients are in complex form and first have to be broken down by soil life. As a result, organic fertilizers also have a natural long-term effect. You only need to fertilize once in the spring and top up every now and then. Mineral fertilizers, on the other hand, are added to the irrigation water every one to two weeks. You can read here exactly how to fertilize geraniums - you will also find valuable information about the nutritional needs of exotic plants.
Summary of fertilizing geraniums:
- When planting, use long-term fertilizers such as compost, horn shavings or organic fertilizeruse
- Following this, fertilize occasionally; mineral fertilizers: every one to two weeks in the irrigation water
- Our recommendation: primarily use organic fertilizers with a high proportion of potassium and phosphate, such as our Plantura organic flower fertilizer
How to cut geraniums
Geraniums are generally very tolerable when it comes to pruning. With standing geraniums, you can create smaller and larger standard trunks or bushes by topiary and let your creativity run free. Those who tend to live on a small creative footing can be content with clipping off the tips of the new shoots in spring to early summer. That way the plants don't shoot into the weed. The mother plant is encouraged to branch and the nipped shoots are ideal for growing cuttings. Learn how this works below.
In rainy weeks, there is an increased risk of rot or mold growth on wilted flowers. To avoid this, you should regularly remove (clean out) the faded inflorescences by hand. This also strengthens the formation of new flowers, because removing the flowers suppresses seed formation and new flowers sprout. It is optimal if you carry out this care measure weekly. A certain subspecies of hanging geraniums (Pelargonium peltatum) does not require trimming because they are self-cleaning. The varieties 'Cascade' or 'Villetta' are particularly popular.
The geraniums are cut back in September/early October for the last time of the year before they are moved to their winter quarters. The long, unwoody shoots are shortened to about four inches, leaving two to three knots per shoot. In addition, all leaves are removed. After a successful hibernation, the spring pruning takes place at the beginning of budding (around the beginning of February). Since geraniums bloom on the new shoot, a radical pruning leads to a particularly large number of flowering shoots.
Summary of pruning geraniums:
- In summer: Occasionally trim shoot tips to improve growth habit
- Weekly: Clean out dead buds to minimize risk of mold and rot
- Beginning of February and September/October: Radical pruning
Tip: If you leave out one or more main shoots when cutting back hanging geraniums and only cut back the side shoots that come off in spring, you can also use them asKeep climbing plants.
Winter geraniums
Geraniums unfortunately don't survive the frosty winters outside of their sunny African homeland. So that you can still enjoy your geraniums for years to come, they must be placed in a protected winter quarters before the first frost. This is ideally a dark, cool room such as a basement. Your geraniums will remain in this until spring after the following preparation:
- Dig up the geranium carefully
- Gently tap the earth from the roots
- Pruning as mentioned above
- Cover the roots in a pot or bag with sand and potting soil
- Put geranium in winter quarters
We only water so that the root ball does not dry out completely. There is no fertilizer at all during the hibernation period.
You can find out more about overwintering geraniums in our special article.
An overview of the most important geranium diseases
Geraniums are floriferous plants given the right site conditions and proper care. However, the pests or diseases listed below can still occur.
Geranium rust on geraniums
Especially when the leaves are wet, the susceptibility to geranium rust is increased. You can recognize an infestation when the leaves turn yellow to brownish and pustules appear on the underside of the leaves. Spots or rings are visible on the upper surface of the leaf, which quickly spread. Since geranium rust is contagious, you should remove and dispose of affected leaves as soon as possible when an initial infestation occurs. You can also support the plant with a plant strengthener and should definitely avoid watering the plant from above. The geranium should also be protected from rain.
Botrytis on geraniums
The so-called botrytis (also called gray mold) is a common fungal disease. Similar to geranium rust, there is an increased susceptibility to wet and cold weather. If your geranium shows rotten spots with gray spore coating, it is most likely affected. Then you should first remove infested parts of the plant and keep the plant drier in principle. Spraying with bio-active agent with field stalk and oats provides additional strength.
Aphids on geraniums
Aphids also often target geraniums. An infestation often occurs in the winter quarters when the plant is dark andlittle grows. When the aphids suck, the geranium leaves curl, making the infestation recognizable. If this is the first aphid infestation, rinse the geranium thoroughly with water. If they occur more frequently, you can also fight the aphids with soapy water.
Spider mites on geraniums
While gray mold and geranium rust usually appear in wet weather, geraniums can be attacked by spider mites in warm, dry weather. The infestation can be recognized by silvery dots on the upper side of the leaf and webs on the underside of the leaf. In most cases, spraying the geranium with water and treating it with a plant strengthener is enough to combat it.
Whitefly on geraniums
Especially in sheltered, warm locations and in winter quarters, geraniums are susceptible to infestation by whiteflies. The pests settle on the underside of the leaves and cause yellow spots on the leaves by sucking. Affected leaves then dry up and fall off. To combat it, you should remove infested leaves and attach yellow boards if infestation is low. Ichneumon wasps are well suited for natural control by beneficial insects.
Summary of the most important geranium diseases:
- In the case of geranium rust, the leaves turn yellow to brownish; sometimes pustules appear on the underside of the leaves; spots or rings are visible on the upper surface of the leaf, which quickly spread; contagious
- In the case of an infestation of botrytis or gray mould, rotting spots with gray spore coating appear
- An infestation by aphids can be recognized by the wavy leaves
- Spider mites leave silvery spots on the upper side of the leaf and webs on the underside of the leaf
- Whiteflies settle on the underside of leaves and cause yellow spots on the leaves by sucking; affected leaves dry up and fall off
In this special article you will also find out what to do if your geraniums have yellow leaves.