Callibrachoa: location, care & toxicity of million bells

Million bells (Calibrachoa) love sun and warm temperatures. This makes them the perfect summer planting for balcony boxes, hanging baskets or hanging flower pots.

The numerous flowers of million bells (Calibrachoa) not only look beautiful, but also attract many insects. With a few tips and tricks you can easily manage the cultivation of million bells, from sowing to overwintering.

Calibrachoa: origin and characteristics

Calibrachoa, often called trailing petunias or million bells, have their genetic roots in South America. However they have since become a popular balcony plant in our country. And it’s little wonder, because in terms of appearance, Calibrachoa are mini-petunias, with the advantage that unlike petunias (petunia), they don’t require deadheading. For a long time it was believed that million bells were actually petunias. However, recent microbiological studies show that they are two different genera belonging to the same family, Solanaceae.
Calibrachoa are perennial herbaceous plants. With shoots up to 60cm long, they can form a hanging carpet of flowers. The flowering period of million bells extends approximately from May to October. In our climate, they do not survive the cold temperatures in winter, which is why the flowers are usually cultivated only as annuals.

Are million bells bee friendly? Calibrachoa provide abundant pollen, but because of the flower shape, it is only accessible to a few insects, such as some species of butterflies. Nevertheless, million bells do their part to create an insect-friendly garden.

The most beautiful Calibrachoa varieties

Whether red, blue or white Calibrachoa, whether single or double flowered or multicoloured – the choice of Calibrachoa- varieties is huge. Nowadays, all commercially available varieties are hybrids, that is, mixtures of many original species.

• Calibrachoa hybrid ‘Trixi Famous Pastel’: As the name promises, this variety combines 3 varieties of Calibrachoa million bells on one rootstock. All bloom in pastel colours: from rose to pink and purple. Compared to similar varieties such as the million bells ‘Carnival’, ‘Trixi Famous Pastel’ also has an impressively even distribution of flower colours.
• Calibrachoa hybrid ‘Callie Painted Pink’: The ‘Callie Painted Pink’ cultivar features a delightful, rather upright, well-branched habit and abundant blooms. In addition, thanks to its pink flowers with delicate white stripes, this million bells is a real eye-catcher for any balcony.

• Calibrachoa-Hybrid ‘Chameleon Atomic Orange’: For this variety, ‘Chameleon’ is an appropriate cultivar description, as it is marked by flowers of changing colours – depending on season and day length, among other factors. In the variety ‘Chameleon Atomic Orange’, the colour spectrum ranges from pink with a yellow centre to yellow flowers with a slight pink tinge.
• Calibrachoa hybrid ‘Aloha Double Strawberry’: The flowers of this Calibrachoa hybrid are double. ‘Aloha Double Strawberry’ features a compact, bushy habit and early bloom.

Tip: The proportion of double-flowered Calibrachoa varieties in the market has been increasing recently. However, think twice before buying them. They do appear more lush – but this is at the expense of insect-friendliness of the million bells. This is because in double flowers, the pollen is present in smaller quantities for insects – and is also even more difficult to reach.

Growing million bells

If you want to bring Calibrachoa home, a few questions quickly pop up. These include: What soil is suitable for million bells? Is my balcony or terrace suitable for cultivation? And when is the best time to plant Calibrachoa? Therefore, in the following sections you will find a detailed guide that answers all these questions.

Companion planting million bells: Generally, combine Calibrachoa with plants that have similar site requirements. That is, all the plants in the arrangement should like the sun and also tend to be heavy feeders. In the window box, for example, Calibrachoa can be combined well with yellow sage (Lantana camara), trailing lobelia (Lobelia erinus) and baby’s breath (Euphorbia hypericifolia ‘Diamond Frost’).

The right location

For Calibrachoa, the recommendation is to grow them in pots, as it is easier to keep them evenly moist and overwinter them if needed. For example, you can grow million bells hanging in hanging baskets or combine them with geraniums in balcony boxes. Growing million bells in the bed is also possible, but not ideal. Calibrachoa have pendulous, long shoots that look especially good in pots.

Sunny balconies, therefore, represent the ideal location for million bells. Partial shade is still tolerated, but you are likely to obtain fewer flowers.

Choosing the correct soil for million bells is also crucial. Calibrachoa grow best in well-drained, nutrient-rich and rather acidic substrates. For example, we recommend our Plantura Organic All Purpose Compost in combination with our Plantura Hydrangea Food. This keeps the pH of the substrate low and prevents iron deficiency, which is common in Calibrachoa.

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Procedure

The most convenient and fastest way to get Calibrachoa on the balcony is through young plants from the garden centre. You can grow million bells from seed just as well.

If you have decided to sow Calibrachoa, you can start as early as February.

1. Fill a shallow tray about 3 inches high with growing soil and lightly moisten the soil. A good soil to use here is our Plantura Organic Herb & Seedling Compost.
2. Spread the seeds on the soil at a distance of 3 – 4 cm each. Only gently press the seed, because million bells are light germinators.
3. Water everything again. To prevent them from drying out too quickly, it’s a good idea to cover the growing tray with cling film, or use a mini-greenhouse.
4. Place the tray in a bright place with a temperature of about 22 – 24 °C and keep the soil moist throughout, but not wet. Then the seeds should germinate after about 10 – 14 days.
5. About 3 – 4 weeks after germination, put the young plants in individual pots. These should be about 7 inches in diameter and can be filled with a mixture of our Plantura Organic All Purpose Compost and our Plantura Hydrangea Food or a similar alternative.
6. As before, the plantlets should be placed in a bright place and protected from drying out. However, the temperature may now be a little lower.

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• Harden the seedlings to bright sunlight and weather by initially placing them outside for only a few hours a day.
• Choose a planter that is larger than the root ball of the seedlings. The pots can easily have a diameter of 20 cm.
• First fill a drainage layer a few centimetres high, for example, using expanded clay.
• The remaining pot can then be filled with the mixture of our Plantura Organic All Purpose Compost and Plantura Hydrangea Food.
• For Calibrachoa, the planting distance is 20-25 cm. Several seedlings in a large pot can create an impressive overall look.

Whether you bought million bells plants or grew them yourself, in May, after the Ice Saints, it’s time to plant them in their final position. There are a few things to keep in mind.

Calibrachoa care

When watering Calibrachoa, the right quantity is important. Especially on hot days in summer, the flowers can draw a lot of water, so watering is required almost every day. However these flowering power-houses should never be left standing in water, because they do not tolerate waterlogging at all. It is therefore best to hold off on watering until the top layer of soil has dried slightly. Calibrachoa in pots are often watered with tap water containing lime. Over the long term, this can cause the pH value to rise, resulting in an iron deficiency, for example. To prevent this, it is best to water your million bells with rainwater.

Since they are very hungry for nutrients, you should fertilise million bells regularly during the growth period from March to September. This promotes vigorous growth and abundant flowering. A suitable fertiliser is our Plantura Hydrangea Food, because like hydrangeas, Calibrachoa have an increased iron requirement and love a rather acidic soil. Of these, 4 to 6 g per litre of pot volume can be mixed into the substrate at the time of planting, and then after two months fertilise again with about 4 g per litre.

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Damage patterns and pests

Calibrachoa have a high iron requirement. Deficiency is noticeable by a lightening of the younger leaves, while the leaf veins remain green. If older leaves turn yellow, this indicates a nitrogen deficiency. In both cases, our Plantura Hydrangea Food can help. By soaking it in water for a few hours, you can further accelerate its action.
You may happen to discover aphids (Aphidoidea) or thrips (Thysanoptera) on your million bells. There are several options for controlling aphids, including the use of beneficial insects and neem-based biological agents.

Since Calibrachoa are usually not cultivated as a perennial in our country, pruning is unnecessary. Even deadheading withered flowers, as is usual with petunias, is not necessary. This is because old flowers inconspicuously recede behind the new ones in million bells. If the growth is too sprawling, you can certainly cut back individual shoots.
Pruning is necessary only if you want to overwinter your plants. This should be done as late as possible – that is, just before wintering.

Are million bells hardy?

With proper care, million bells have no problem with high temperatures, but the situation is different with cold: here, Calibrachoa are not hardy. Overwintering Calibrachoa can still succeed. To do this, you should shorten the shoots before the first frost to about 10 cm and then put the plant indoors, in a place as bright as possible, at about 10-14 °C. You do not need to fertilise million bells during the wintering, and watering should be restricted. Then in May, after the Ice Saints, the plants move back into the open air.

Propagation

Propagation is possible by seeds or cuttings.

Nowadays, there are actually only hybrid varieties of Calibrachoa. Propagation by seed is still possible, but the appearance of the new plant will be a surprise. It may happen that the daughter plant has little in common with its mother plant. To harvest the Calibrachoa seeds, pick the small green seed pods in the autumn, bring them indoors to dry and place them on a sunny windowsill. After a few days, the capsules usually burst open by themselves and small, black seeds appear. Store them in a dry, cool place until you sow them in February, as described above.

Calibrachoa propagation is possible by cuttings. In this way, you create a clone of the mother plant, so to speak – so you know what the propagated plant will look like. The best time for this is approximately between the end of August and the beginning of September. This means the freshly rooted cuttings must be overwintered.

1. Cut off about 10 inches of healthy, flowerless shoot tips from your million bells.
2. Remove all the leaves on the bottom 5 cm. Then put the shoots in pots about 7 cm in diameter, filled with a moistened growing soil. A rooting powder can be added to the soil for better growing.
3. Put the pots in a bright place with temperatures of 20 – 24 °C.
4. Keep the substrate very moist, especially in the first few weeks. It also helps if you repeatedly spray the plant with water from an atomiser.
5. Growing was successful when you see the first new shoots.
6. To get the young plant through the winter safely, place it in a bright, rather cool place indoors before the first frosts. Optimal temperatures are between 10 and 14 °C.

Are Calibrachoa poisonous?

Since they belong to the nightshade family, like potatoes, million bells are slightly poisonous to humans and animals. This is mainly due to the alkaloids it contains, such as solanine.

African daisies (Osteospermum and Dimorphotheca ) are perennial flowers for sunny sites. In our article about the popular summer flower, you will learn everything about its planting, care and wintering.