The Zimmercalla or Zantedeschia, as it is also called, is a fairly widespread and popular plant. The reason for this is their unusually shaped flowers, which make them elegant eye-catchers. In order for them to develop them in full beauty and keep them for a long time, the right care and suitable wintering measures are crucial.

Variety selection – room or garden?

As the name suggests, all forms of indoor calla can be used as indoor plants. However, they can also stand outside in summer, ideally in pots or tubs. The selected varieties do not have to be hardy for this. Caution is only required when temperatures drop. White varieties should not be cooler than 16 ° C. Colored and spotted shapes should even be brought inside at temperatures below 18 ° C.

The exception here are special hardy Zantedeschia, such as the Calla Crowsborough. These can stand outside all year round and withstand temperatures of down to -20 ° C. However, they need the right location for this.

When making the selection, it is important to know where the room calla should and can later be.

Calla or room calla?

The terms calla and room calla are often equated with each other, but actually two different types are hidden behind them.

Although these are very similar, they differ fundamentally in terms of winter hardiness. The calla is a hardy marsh plant that can be planted freely in the garden. Ideally near water, for example by a pond or watercourse.

The room calla, on the other hand, thrives best in sheltered locations or on the windowsill. It does not survive even autumn temperatures.

Here too, attention should be paid to the variety of varieties.

Tip: The room calla and calla can be recognized by their Latin names. The room calla has names that begin with the word “Zantedeschia”, such as Zantedeschia aethiopica.

The calla or marsh calla, on the other hand, has the word “calla” in its name, as can be seen in the calla palustris.


Whether calla or room calla, garden or window sill, the plants with the noble flowers need a light location. A place that gets plenty of sun but is spared the blazing midday sun is ideal.

The Zantedeschia also needs to be reasonably warm. Temperatures between 16 ° C and 20 ° C are ideal for white-flowering varieties. Colored or patterned species thrive optimally at 18 ° C to 21 ° C.

In addition, drafts and cold wind are poorly tolerated by the plants, so the location should also be protected. For the outdoor planting area, corners and walls, hedges and other dense plants are recommended.


The room calla makes hardly any demands on the substrate. Commercially available potting soil is sufficient. Bucket soil or loose garden soil can also be used without any problems.

The only important points when it comes to the substrate are its age and cleanliness. Callas, and especially indoor callas, are relatively susceptible to disease and pests. If the substrate is of poor quality, has already come into contact with diseased or infected plants or is permeated with pathogens, the calla will also die quickly.

When buying, you should also pay attention to quality. Cheap potting soil usually costs more in the long term.

Proper care

Once in the right place, the Zantedeschia needs very little maintenance. All that is required is regular watering and fertilizing to ensure it thrives well.
Blending is only necessary if necessary.

The situation is different when it comes to caring for callas that are sick or infected by pests. These require a little more effort.


The indoor calla, like the swamp calla, needs plenty of water. Regular watering is therefore essential. At least in the growth phase and during the flowering period.

The following tips are important when pouring the calla:

  • Use water with a low calcium content, for example rainwater or stale tap water
  • Water abundantly during growth and flowering, the water can stand in the saucer or planter
  • Make sure there is adequate ventilation, the strong watering increases the risk of rot
  • Keep the room calla drier after the end of the flowering period and during hibernation, but still water occasionally
Tip: With the room calla starting in January, increase the watering slowly and gradually until March.


From the end of February or the beginning of March, the preparation for flowering begins. At this point the Zantedeschia has an increased need for nutrients. Accordingly, it must also be fertilized.

Commercially available flower fertilizers are suitable for fertilizing the room calla. Liquid fertilizer is particularly useful for flowering plants.

When fertilizing the calla, the following are important:

  • Begin with regular fertilization with the irrigation water at the end of February or beginning of March
  • Fertilize every 14 days before flowering
  • The indoor calla shows the first colored bracts, gradually increasing the fertilization
  • Fertilize every week during the flowering period
  • If there are no or only a few flowers, the additional nutrient supply must be increased


In contrast to watering, regular cutting of the plant is neither necessary for shaping nor for stimulating growth. Even the flower does not suffer if the blending of the room calla fails.
In fact, cutting is only necessary if dried or withered parts of the plant appear. You do not have to make particularly generous cuts here. It is completely sufficient if only the affected sections are removed with a little green.

However, cutting the room calla is mandatory if it has been attacked by pests. Then the green around the affected parts should also be removed.

Repotting and repotting

Repotting or moving the calla is only necessary if the plant is too big for the container, if the location is unsuitable or if there is an infestation with diseases or pests. Likewise if rot spreads in the substrate or the earth is used up.

So the list of possible reasons is quite long. No special features need to be taken into account when choosing the soil or the pots.

Repotting or moving the calla:

  • Carefully remove the plant from the pot
  • Thoroughly remove the substrate from the roots
  • Rinse the tubers with water that is not too cold and lime-free
  • Trim roots that are too long or intertwined
  • Place in the new pot or the dug out planter
  • Press the earth down
  • Flood the plant
Tip: Ideal times for moving and repotting are spring after the last frost and autumn before the first frost. Even if the room calla won’t get any frost anyway, changing soil before or after the flowering period is ideal.


The propagation of the room calla can be done in two ways. The Zantedeschia can be propagated using seeds. However, the tuber can also be divided.

However, pulling from seeds is tedious. Even after the plants have sprouted, it usually takes a few years for the indoor calla to bloom for the first time.

Propagation from tubers, on the other hand, is very easy. To do this, the tuber only needs to be divided when repotting or moving and the resulting parts have to be planted separately. Because the tuber, like the upper section, is comparatively vulnerable, a very sharp and clean knife should be used for this purpose. In addition, the substrate must be of high quality. After dividing the tuber, it is necessary to water and fertilize the zantedeschia abundantly.

Wintering of the room calla

With the room calla, preparation for winter should begin as soon as the last flower has fallen by severely restricting watering and fertilizing.

Normally, some leaves will turn yellow and eventually dry up. These should be removed as they can increase the risk of rot and mold.

The wintering of the room calla:

  • After flowering has ended, remove any dried-up parts
  • Let the substrate dry slightly
  • Put the room calla in a cool, frost-free room for the winter
  • The temperature should not exceed 10 ° C for white Zantedeschia and 14 ° C for callas with colored or patterned flowers
  • During the hibernation, room callas still need light

Preparing for spring

From January the calla can slowly get used to higher temperatures, more light, regular watering and fertilization.

Parts of plants that have dried out or withered during hibernation should be removed. Because even after the winter rest, these represent an increased risk of mold and rot. It does not matter whether the dead sections are dry or withered.

Tip: An overly abrupt change from cold winter quarters to warm summer quarters must be avoided as a matter of urgency. It is best to first slightly increase the temperature in the winter location.

Winter protection of the hardy calla

The hardy calla, as the name suggests, can withstand frost and can therefore overwinter outdoors. However, it should be in a protected location for this.

The preparation of the free-standing callas requires nothing else than that of the room calla. Additional watering and fertilization must be reduced. In addition, the plants can be pruned after flowering if necessary.

Before the first frost, it helps the calla to be protected with leaves, fleece, straw or brushwood. Although this additional winter protection is not absolutely necessary for really hardy and robust varieties, it does save their strength. The better the plant is protected, the more it will sprout in the following spring and the richer the flowers.

Depending on the length and severity of winter, the winter protection can be removed as early as February or not until April. Temperatures that are just below zero are tolerated without any problems. However, higher minus temperatures can freeze the young shoots to death.

Typical diseases and pests

Calla and room calla are quite susceptible to fungi, bacteria, viruses, spider mites and aphids. Even if they are severely attacked by the pests mentioned, commercially available pesticides and removing the affected parts are sufficient to save the Zantedeschia.

It is different with rot, fungi, bacteria and viruses. Quick action is required here. On the one hand, the plant must be treated accordingly with special agents. On the other hand, it is necessary to remove the affected areas generously. It is also helpful to repot or move the plant. The used earth should be removed generously and immediately destroyed.

If the room calla or calla is already badly affected, even comprehensive rescue measures can fail. If the Zantedeschia shows no improvement within a few weeks or if the tubers are already rotten, the plant must be destroyed – because then it can no longer be saved

Tip: Under no circumstances should the cut parts of the plant or the substrate end up on the compost, as pests and pathogens would only spread more and infect other plants.

Examine the plant regularly, preferably when watering, for discoloration, traces of eating, coverings and pests. The earlier the infestation is discovered, the greater the chances of saving the calla.

Is the room calla poisonous?

The flowers, leaves and bulbs of the indoor calla and calla are poisonous. For this reason, it is essential to ensure that children and animals cannot accidentally eat them.

In addition, so-called guttation occurs in the plants with the noble flowers. Excess water is released to the outside via the leaves and drips off the plant. However, the Zantedeschia is not pure, harmless water. Instead, various irritating substances are dissolved in it. If there is contact with the skin or if the drops are licked off or swallowed, wheals, reddened areas and inflammations develop. Vomiting, diarrhea, fever and chills may occur.

This poisoning can lead to life-threatening conditions, especially in very young children, small animals and sensitive people. The plants should therefore always be out of the reach of children, animals and allergy sufferers.

Tip: Wear gloves when caring for the Zimmercalla, they prevent accidental skin contact. Place the plant on wipeable surfaces to avoid staining from the falling drops.

The room calla is an easy-care and decorative plant, but it is comparatively susceptible. If it is examined regularly and treated with caution because of its toxicity, it is suitable for beginners as well as for experienced plant lovers.

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