Geraniums (pelargoniums) overwinter

The ideal time to put the plant, which originates from South Africa, into hibernation is late autumn, when most of the leaves have already turned orange-brown or have fallen off. But it can happen that green leaves and even buds are still showing. However, if temperatures are near freezing for several nights or if the first frost shows up during the night then geraniums should be moved to a safe place to overwinter.

• depending on the temperature between the end of October and the end of November
• tolerate light frost down to -5 degrees in winter
• survive one to two days at temperatures slightly below 0 degrees

The pruning in winter

If the pelargonium is to overwinter, one of the most important measures is to cut back the plant. Because if they are only put out of the garden into the winter quarters, they usually don’t survive it. However, before pruning can take place, all leaves should be removed, regardless of whether they are still lush green or already dried up. Because the leaves of the geranium are very susceptible to pests and diseases, especially in the winter quarters.

• For overwintering geraniums, a pruning of approx. 1/3 to 2/3 is sufficient
• geraniums should still be around 17 cm to 20 cm in size
• Two to three thickened knots should remain per side shoot
• excess soil that becomes present at the roots is removed
• however, the fine root branches should remain somewhat covered

Various options for wintering

However, geraniums can be stored in many different ways over the winter, depending on the space available.

• in the clay pot
• bare-root wrapped in newspaper and plastic bags
• in the burrow
• in the flower box

Overwinter bare-rooted in the bag

Many hobby gardeners choose the plastic bag method to overwinter the geraniums. With this variant, the geraniums are placed in a bag and hung upside down. It should be noted:

• trim any long roots to one length
• just wrap the root ball in newspaper, which regulates moisture in winter
• wrap in a thin plastic bag and do not tie too tightly
• however, a little air is allowed to reach the roots
• therefore poke small holes in the bag
• and then hang upside down

clay pots

Another option for geraniums to overwinter is in clay pots.

• remove the soil from each individual plant after pruning
• Put three to four plants in a pot
• a mixture of potting soil and sand to cover the roots in winter

Overwinter in the burrow

Plant lovers who own a garden can successfully get geraniums through the winter in a hole in the ground. For this it is necessary:

• dig a hole about 80 cm deep
• fill it with brushwood, straw or newspaper
• then insert the pruned, leafless and soil-free plants
• cover with the excavation
• and put a straw mat over it for extra protection
• the outside temperatures must not fall below -2 degrees

In the flower box

The most common way, however, is to let geraniums overwinter in a flower pot or in a flower box.

• Do not take plants out of the ground
• Cover roots loosely with a little potting soil and sand

Care instructions for the winter

Geraniums require little care in winter. While the plants in the plastic bag survive the cold season without water, geraniums in the flower box should be watered sparingly every few weeks so that the soil does not dry out and the plant dies. Fertilization should be avoided completely in winter, but the plants should be checked regularly for pests.

location in winter

Geraniums in clay pots and flowerpots are best overwintered at temperatures of 5 to 10 degrees in a bright place. The following applies: the darker the room, the lower the temperatures must be. Because if the plants are stored too warm or too dark with this method, they can not only sprout prematurely, but also form long, thin shoots.

The ideal location for bare-root storage in winter is a dark, cool room such as the basement, garden shed or garage with temperatures between 2 and 10 degrees.

For the plastic bag method, a frost-protected, cool and dark place to overwinter is recommended. A garage, a basement or a frost-protected garden shed is well suited. Because it is extremely important that you do not expose the plants to direct sunlight so that they do not sprout and die as a result of a lack of water.

plants in spring

If the geraniums have successfully survived the winter, some work is required to prepare them for summer. In this way, the plants are pruned, replanted and moved to a bright location on the windowsill so that they can finally get their usual place outdoors again when the temperatures rise.

• cut back to 10 cm in February or March just above the bud
• this allows the geraniums to grow new shoots
• put back in flower boxes with fresh soil
• put it in a warm and bright place, for example the sunny window sill
• and water more often
• first fertilization
• from mid-May after the ice saints they will be given their place outdoors again
• bring the boxes back into the house overnight when it gets cold

Diseases

If geraniums do not receive adequate care, the plants can quickly become ill and be infested with pests. That is why faded inflorescences and withered leaves must always be removed in good time so that they cannot form a basis for diseases and pests.

Bacterienkrankheit

If geraniums are affected by bacterial disease or bacterial wilt, this is an infection that may already be present in the plant when it is being reared, but does not always have to break out.

• oily but transparent spots form on the leaves
• Affected areas wither, turn black and die
• risk of infection
• therefore remove affected sticks immediately
• prevent with proper care
• not too much fertilizer
• no excessive watering
• Avoid injuries to shoots and leaves
• no wet leaves

Geranienrost

The most common disease affecting geranium canes is a fungal infection called geranium rust. The leaves take on a yellow or brown color.

• brown spots or rings on top of leaves
• yellowish and brown pustules on the underside of the leaves
• Geranium rust is very contagious
• quickly spreads to other plants
• therefore always pour into the soil and not onto the geraniums
• can also be caused by longer rainy days

Grauschimmel

Another disease that geraniums often suffer from is gray mold or gray rot, which shows itself through special characteristics.

• grayish black spots with a gray lawn of fungi
• or the plants show the disease by rotting
• The reason is too much watering, injuries, too cool weather and lack of light
• Control gray mold only by removing the affected leaves
• regular follow-up is important

cork stains

If not cared for correctly, cork stains form on the leaves of the plant, which do not look very nice, but are not as harmful as gray mold.

• brownish and light pustules appear
• the reason for this is insufficient light
• too much water
• irregular watering
• but also cold irrigation water, which is poured onto plants that have been warmed up by sunlight, can be a trigger

iron deficiency

Even if iron deficiency is not dangerous for geraniums and the cause is a lack of nutrients, it should still be treated with iron fertilizers.

• yellowish leaves with green axils appear
• preventive measure is regular fertilization with complete fertilizer

pests

Like all garden and balcony plants, geraniums can be affected by pest infestation, even if they are only rarely visited. Proper care for geraniums, sufficient planting density and appropriate watering are extremely important to prevent pests and ensure that the flowers are strong and healthy.

Aphids especially the striped potato aphid

• combat with a light, environmentally friendly lye mixture consisting of washing-up liquid and water
• important here is that it is poured exclusively into the ground
• at temperatures above 15 degrees, gall midges or ladybugs can be used

Cutting rot or blackleg

• at ground level, the stems are blackened
• rapid spread of the disease
• occurs due to excessive humidity and soil that is too wet
• Compared to other plants, geraniums need dry air

Spider mites and thrips (thunderstorm creatures, flies, worms)

• Spider mites can be treated with soapy water from soft or curd soap
• Appears when the humidity is low and disappears when the humidity is over 60 percent
• using sprays can cause damage to the plant
• rapid spread to other herbs (basil) and plants
• therefore, as a precautionary measure, remove affected areas
• if thrips infest geraniums, the plants should be isolated
• fight with soapy water