The emblematic Mediterranean citrus plants delight our springs and summers with their pure white flowers, sometimes slightly pinkish, and above all delightfully fragrant. Additionally, their evergreen foliage presents obvious interest throughout the seasons thanks to its bright green shine. But it is especially in winter (between October-November and April-May) that citrus become attractive. Indeed, their fruiting enchants both the taste buds and our eyes with the splashes of color they bring to a garden or terrace. And depending on the cultivated species, these fruits display shapes, sizes, and colors of great variety.
These small pleasures associated with citrus cultivation are accessible to everyone. Although not very cold-resistant, citrus can be grown throughout France. Obviously, in the ground in the “orange zone” or in the Mediterranean area, in pots elsewhere. This cultivation does not present particular difficulties, but it requires regular maintenance. Especially if you want abundant fruiting. That’s the secret!
Discover the main tips for your lemon trees, orange trees, mandarins… to fruit abundantly year after year.
If you live on the French Riviera, and particularly in the “orange zone” or in Corsica, you are fortunate! Indeed, you can cultivate, in the ground, most of the species of the Citrus variety, namely lemon trees, orange trees, mandarins… Venturing inland, staying in the Mediterranean area, the possibilities diminish, but it is still possible to grow in the ground a lemon tree, a mandarin tree, a bitter orange tree… On the Atlantic coast, some citrus also grow quite easily, although fruiting is not always guaranteed.
In addition, everywhere, cultivation in pots is necessary. Provided you have an outdoor space (garden, terrace, balcony, patio…) where your citrus will spend the beautiful season, and a veranda, a cold greenhouse, a winter garden, or at least a shelter without frost relatively bright. Indeed, keeping a lemon tree, an orange tree, or a mandarin tree outside, under a winter veil, in the middle of winter with temperatures dropping below -5°C, is impossible. So, a citrus must overwinter in a bright room with a temperature of around 5 to 10°C.
Similarly, to make a citrus fruit, forget about cultivation in our overheated apartments in winter. It is simply impossible, as citrus must overwinter: they need a period of relative cold (remember 5 to 10°C) to bear fruit.
If all conditions are met, you can grow in a pot a lemon tree, in particular the four-season lemon tree, or the refined caviar lemon, an orange tree, a mandarin tree or a clementine tree, a kumquat, a citron, or even a surprising Buddha’s Hand…
However, two exceptions to the rule: the Poncirus trifoliata and the calamondin. The first is a thorny lemon tree that withstands -15°C and therefore can be grown in the ground (almost) anywhere. The second is a hybrid of kumquat and mandarin that is grown in a pot in an apartment, where it withstands the atmosphere. Both fruit quite easily.
Soil and exposure, two key elements for citrus fruiting
Planting in the ground
In the ground, a citrus must benefit first from an optimal situation. Therefore, it must be planted in full sun, ideally in a south-facing location, and especially in a place protected from cold or dry winds. Moreover, citrus do not like sea mists very much.
As for the soil, offer your citrus perfectly drained soil, preferably light (or lightened with pumice, rich in iron, gravel, or coarse sand to promote drainage). As for the nature of the soil, it will preferably be neutral or slightly acidic. Calcareous soils are not very appreciated by citrus, unless heather soil is added.
Finally, leave enough space for your citrus, a little for their span, but above all because of their shallow root system. Very superficial, it can be annoying for other plants growing nearby.
Pot planting
Grown in pots, citrus need a relatively light substrate made up of garden soil, potting soil, a little sand, and compost. Of course, the pot must be filled at the bottom with a layer of expanded clay or gravel.
They need to receive enough light. From October to November until March-April, citrus spend the winter in a bright room with a temperature of 8 to 10°C. They should not be exposed to direct sunlight, as they can burn. As soon as the risk of frost has passed, they can be placed outdoors, first in partial shade, illuminated by the morning sun, for two weeks to acclimatize, then in full sun and protected from the winds.
The importance of careful maintenance to obtain beautiful citrus
Maintenance is certainly the most important element for getting beautiful fruit from your lemon trees, orange trees, mandarins… especially if grown in pots. However, the same maintenance can be applied to citrus grown in the ground, although these defend themselves better than those grown in pots.
When we talk about maintenance, we must consider several essential gestures: watering, fertilizing, pruning, and transplanting. Let’s detail all these gestures that are the ABC for your citrus to fruit.
Watering citrus
Remember one essential thing: citrus are true thirsty plants! It is indispensable to water them very regularly in spring and summer. Therefore, abundant watering every 2 to 3 days is recommended, simply letting the substrate dry on the surface between each watering. In the ground, watering once a week may be sufficient. In pots, never let water stagnate in the saucer or at the bottom of the pot.
From autumn and in winter, watering will be reduced but will continue. Indeed, citrus are evergreen plants where the sap continues to circulate. However, they need a period of winter rest. A small watering once a week is sufficient for citrus in pots. Citrus in the ground can cope with the weather conditions.
Watering is always done with rainwater, ideally at room temperature, as they do not appreciate calcareous water.
Fertilizing citrus
If they are thirsty, citrus are also very greedy. Their nutritional needs are enormous, especially during the flowering, setting, and fruiting periods. Therefore, they need very regular fertilizer inputs. Regularity is indeed an important concept. If you start fertilizing your citrus, continue to do so very rigorously, as they would not tolerate intermittent fertilizers.
From March to September, a slow-release fertilizer should be applied, on moist substrate, every 15 days. Ideally, a fertilizer, both organic and mineral, special for citrus is perfect, but you can also use a fertilizer rich in nitrogen and potassium, but also in phosphorus and trace elements. Citrus also need iron, which can be provided by adding pumice to the substrate.
In the ground, citrus should manage on their own if the planting was done in suitable soil. However, fertilization can be done once in the season.
Moderate pruning
Whether grown in the ground or in pots, citrus can be pruned, but always in moderation. In fact, a citrus in good health should offer flowers, leaves, and fruits. However, if you do not know how to prune your citrus, it is better to abstain than to do it badly. Pruning remains optional. And if pruning is necessary, do it after harvesting the fruits.
It consists mainly of removing dry or dead branches and airing the center of the bush by cutting out branches that tangle or cross, or that grow inward.
And as a reminder, always use a well-sharpened and perfectly disinfected pruning shears with alcohol.
Regular transplanting
Like all plants, citrus need to be transplanted regularly, on average every 3 years. Thus, with new substrate, they will satisfy their great nutritional needs. However, it is recommended to transplant them in the same pot or in a slightly larger container. Simply scrape off the “old” soil well on the root system.
If your citrus is difficult to transplant because of its size and weight, a topdressing is sufficient. Topdressing consists of removing a few centimeters of substrate on the surface and replacing it with new soil.
Surveillance of pests and diseases
Citrus can be sensitive to attack by pests or diseases that inevitably affect fruiting. Take advantage of the care you provide to your citrus to closely monitor any suspicious appearance of aphids or scale insects. Similarly, if the leaves turn yellow or fall off, act promptly!
Citrus in the ground or citrus grown in pots that spend spring and summer outdoors should be pollinated normally by wind or insects, and especially by bees. In fact, citrus are self-pollinating plants that do not need the presence of another nearby plant to be pollinated. There are therefore no male or female feet in citrus.
So, if your citrus blooms and develops in an environment where biodiversity reigns (and if, of course, you have followed my maintenance advice to the letter!), you should get fruiting. However, if your citrus does not have enough wind or does not benefit from the work of pollinating insects, you can favor its fate by pollinating the flowers yourself. Just move the pollen from the stamens to the pistil, present in the same flower, with the help of a very fine and flexible brush. With the bristles of the brush, collect the pollen and then tap the pistil. And voilà!
