If you don’t have a citrus plant in your living room, it’s really your own fault, you’re missing out on a delicious fragrance that offers air purification and aromatherapy in one. In most cases, no citrus plant enriches the household because the care seems too complicated. That’s why we’re going to introduce you to the bitter orange, the plants and how to care for them. You’ll find that there are easy-care citrus plants for beginners whose fruit can also be made into delicacies.
Table of Contents
Plants, location and growth
Citrus plants are the epitome of exoticism, but (unfortunately for us) there is a reason for that. Citrus plants come from warm regions. There they are used to temperatures at night, which rarely fall below freezing.
So we can only keep citrus plants in pots that are protected over the winter. On the other hand, they feel quite comfortable in our rooms. Our optimal comfort humidity level is in a rather dry range, around 45 percent. Usually it is actually a bit higher and the citrus plant gets along well with that. In any case, you don’t need to turn your room into a steam room for the sake of your citrus plant. Citrus plants grow well in perpetually humid tropical areas, but they also tend to catch all sorts of fungi.
The bitter orange is therefore the ideal houseplant for normal living spaces. It needs a light location, preferably in the sun, without noticeable draughts.
In summer, the citrus plant likes to enjoy fresh air, in the sun or in the (bright) partial shade. Here, too, she would like to be sheltered from the wind.
The bitter orange is an evergreen tree that could grow up to ten meters high, but only reaches heights of around two meters in a pot. The leaves of the bitter orange are darker and larger than many other species. The tree develops a rounded crown. The plants available here are often grown on a leafless standard. But there are also bitter oranges that tend to be grown in the form of a bush.
The care of the bitter orange
The care of citrus plants is generally much less complicated than many indoor gardeners suspect. You can keep them in the room quite normally without having to constantly be around with water sprayers like with some jungle plants.
Brightness and protection from drafts are important. Otherwise, all you need to do is water the bitter oranges regularly and fertilize them occasionally during the growing season.
Normal soil is suitable as a substrate, which can be acidified a little. You can e.g. B. do this by occasionally mixing your coffee grounds into the potting soil. It has a slightly acidic pH value, contains everything the bitter orange needs in terms of nutrients and also ensures that the soil has a nice, loose crumbly structure. For bitter oranges that need to be overwintered quite warm, you could try coconut substrate. This also prevents the development of fungi.
The coffee grounds contain iron, but the bitter orange needs quite a lot of it. When the leaves turn light green to yellow, it’s time for a special citrus fertilizer with increased iron content or an iron-only supplement (if the leaves are already yellow).
Bitter oranges should be watered in the morning or evening, not in the blazing sun, with soft (low-lime or stagnant) tap water or rainwater. Although Citrus aurantium is a very robust citrus plant that even tolerates pH values in the slightly alkaline range, if you constantly water it with hard water, it could become too much.
In the growth phase from spring to the beginning of autumn, the bitter orange needs quite a lot of water. During the winter rest period, watering is carried out more carefully. Waterlogging should be avoided. Bitter oranges develop very fine roots that quickly die off when exposed to excessive moisture. Overall, the water requirement of the citrus plant is rather moderate. The substrate must never feel permanently wet, the surface must always dry in between. However, the root ball must not dry out either. A lack of water can be recognized by their curling of their leaves slightly.
To cut
You should prune your bitter orange once a year to maintain or improve its shape. This applies to tall stems that have already developed a crown and to plants that are supposed to grow more in the form of shrubs. Pruning takes place in spring.
If a clear stem has not yet developed a crown, you can help the bitter orange to develop a dense, well-closed, round crown by pruning twice a year, in spring and autumn. It takes about two to three years to build a nice compact crown.
If this has been neglected and a bitter orange shows a very light crown, you are welcome to cut it back heavily. It will then sprout again with numerous branches. The same applies when a bitter orange has grown so large that the crown develops too much outwards.
hibernate
Bitter oranges are really hardy and the citrus plants that can handle the cold best, but minus 5 degrees is the end for them too. It usually gets colder in the German garden. A citrus plant must therefore be protected over the winter. The bitter orange is the citrus plant that you can really relax with when it comes to overwintering, because it does a lot without complaining.
A bitter orange that is only kept indoors can also overwinter in a heated room, but the location should be bright. It is then kept fairly dry. The cooler the location, the less water the bitter orange needs. The soil should always dry out significantly first, if you water too much, the plant will respond with leaf shedding. Then you should keep the bitter orange even drier. In German households, citrus plants are often kept too wet. Well intentioned, but in case of doubt the death of the bitter orange.
A cool room with temperatures between 5 and 10 degrees is ideal as winter quarters for a bitter orange in the bucket, but there must be sufficient light. If you don’t have a bright room with such temperatures, you can provide brightness with a plant light. How much brightness depends on the temperature, the higher it is, the more light the bitter orange needs. The bitter orange is planted before the first frost and left in winter quarters until spring, during which time it is not fertilized.
Bitter oranges that have wintered too dark tend to develop soft, thin shoots and oversized leaves. If this occurs with your bitter orange, you can take countermeasures by getting a lux meter (by mail order, garden accessories) and measuring the light intensity. Measurements are taken in the middle of the day with a slightly overcast sky close to the plant. At least 1500 lux should be available to the plant for several hours a day.
diseases and pests
Not only do we find the citrus plants attractive, but also around 250 different insects, some of which have specialized in the tasty citrus plants. In addition to citrus leaf fleas, these include black and white flies as well as scale insects, mealybugs and aphids. They suck the sap. Their subsequent excretions provide a breeding ground for fungi and transmit viral diseases.
The bitter orange is also exemplary in this respect. When properly cared for, it is very rarely attacked by diseases and pests. But only if it’s in the right place. If there is no cool winter quarters for a large bitter orange in the tub, there is a high probability that some of the animals listed above will find their way onto your bitter orange. The probability is even so great that it is recommended in this case to do without citrus plants instead of exhausting oneself in the fight against all sorts of small animals.
However, if the keeping conditions can be “just about” met, the hardy bitter orange is the best citrus plant for a winter attempt. If “only” spider mites appear, you can combat a small infestation with a solution containing soap and alcohol. Whether insecticides can be used indoors (against other pests) without endangering people should certainly be considered carefully.
species and varieties
The citrus plants are a genus of the rue family, which are native to the tropical southeast of Asia and have quickly spread to all warm regions of the world because of their delicious fragrance and tasty fruits.
All citrus plants like to crossbreed across all species. Therefore, the botanical classification of the various citrus is highly complicated and controversial. In 1753, Carl von Linné “ordered” the genus Citrus into five representatives:
- Citron (Citrus medica)
- Lemon (C. medica var. Limon)
- Bitter orange (C. aurantium), which should not be confused with the three-leaf orange (Poncirus trifoliata), which is also called bitter orange but does not belong to the citrus genus
- Sweet Orange (C. aurantium var. sinensis)
- Pampelmus (C. grandis)
The Citrus aurantium later turned out to be a hybrid. The name is therefore often supplemented today by a crossing sign: Citrus × aurantium. The Citrus (×) aurantium not only includes the bitter orange described here, but all citrus plants that have arisen from a cross between a tangerine (C. reticulata) and a grapefruit (C. maxima). These fruits (plants) are again divided into several groups of varieties:
- Satsumas: Citrus × aurantium of the Satsuma group
- Pomelos: Citrus × aurantium of the Pomelo group
- Oranges: Citrus × aurantium of the Orange group
- Grapefruits: Citrus × aurantium of the grapefruit group
- Clementines: Citrus × aurantium of the clementine group, and ours
- Bitter oranges: Citrus × aurantium of the bitter orange group
The crossing that produced the Citrus × aurantium probably happened in southern China. The plants have been known in Europe since the Middle Ages, and bitter oranges have been planted in Spain since the 11th century.
The citrus × aurantium of the bitter orange group comes in a few different varieties. For example the normal bitter orange and the chinotto (C. aurantium myrtifolia), slower growing and, in contrast to the normal Citrus aurantium, without thorns.
There are several varieties of the normal bitter orange and the Chinotto, although it is sometimes quite fun with the varieties. For example with the Citrus aurantium “Fasciata”, which in German is called “Landsknechtshosen-Pomeranze” because it is striped like the trousers of these historical mercenaries.
If that’s not enough for you, it goes on: The Citrus aurantium can (like all citrus plants) cross with any species from one of the other five genera of the Citrus, it does so or is bred in this way. This is how other varieties are created:
- Citrus bergamia or bergamot
- a whole group that grew out of bitter orange and citron, or bitter orange and lemon, or bitter orange and lime
- Citrus Bizzaria or Bizarre Orange
- a hybrid of citron and bitter orange
flower and fruit
The bitter orange blooms depending on the growth rhythm, usually in May/June for us. In principle, however, flowers can appear throughout the year. Bitter oranges can bear flowers and fruit at the same time. If a bitter orange is proving to be lazy, you probably watered it too eagerly in winter. Then you can perhaps stimulate the bitter orange to flower with a reduced watering for four to six weeks.
The bitter orange produces hermaphrodite and all-male flowers that invite insects to fertilize with their strong scent and nectar. The orange-colored tart fruits are ready for harvest in January when they bloom in May.
The fruits, which are special forms of the berry, can be processed in many ways, to orange peel and orange marmalade, to Curaçao or bitter orange lemonade, as a fragrance component in a perfume, to orange blossom water and bitter orange oil. The synephrine contained in the bitter orange is also said to be useful as a fat burner.
Conclusion
The bitter orange is a pretty exciting type of citrus plant. If you want to find your favorite variety, it is definitely worth taking a closer look at the varieties and cultivated forms.
