It is the epitome of the sunny south and one of the most popular container plants of all – the olive tree. How to properly care for your olive tree.
With an olive tree (Olea europaea), or a real olive tree, you can bring the dream of the sunny south onto your own terrace. The Mediterranean plant belongs to the olive family (Oleaceae) and has been cultivated since the fourth millennium BC – not only in the Mediterranean region, but also in the Middle East and Africa. This makes it one of the oldest known useful plants. With its silver-gray foliage, the olive tree is characteristic of the Mediterranean region and carries a strong symbolism. Even in ancient times, olive leaves were a symbol of peace. A wreath of olive branches was the highest honor at the Olympic Games.
The Mediterranean plant is very slow-growing, but in its Mediterranean home it can grow up to 20 meters high over the decades. In contrast, the olive tree reaches a maximum of 1.50 meters in the bucket. Olive trees get very old in nature. A few specimens are known that are 1,000 years old or more under their belt. The smooth, silvery-green bark of the trees changes to a cracked bark with age. Olive trees gain in aesthetic appeal over the years. The older the trees are, the more picturesque they are.
Olive trees have characteristic, narrow leaves that are dark green on top and silvery gray on the underside. The shimmering color is created by fine hairs that reduce water evaporation from the tree and thus protect it from drying out. The leaves are alternate and have short stems.
The grape-like yellowish-white flowers of the olive trees appear in May and give off a delicate fragrance. They stand on two to four centimeters long panicles, but are generally rather inconspicuous. Caution: Olives usually only bloom when they are four to six years old, the first fruits develop from around the seventh year of standing.
The fruits of the olive tree are oval and change color from green to brownish to black as they ripen. In the middle lies a large seed. Olives cannot be eaten raw, they must be boiled or pickled. A second sapling as a pollination partner is an advantage so that fruits ripen from the flowers, because cross-pollination increases the harvest yield. For the home garden there are also a number of self-fruiting varieties that bloom reliably and bear fruit every year. With increasing age the trees become more productive, although they only bring a good harvest every other year.
Olive trees love sunny, warm to hot places and are therefore suitable for south-facing balconies and terraces as well as the cold and temperate winter garden. The silver-gray tub plant looks particularly beautiful in a terracotta pot in combination with roses, oleander, leadwort or mallow. Because it grows slowly and takes up little space, the olive also fits very well on small balconies. In the mild Rhine Valley climate with winter temperatures not below minus five degrees Celsius, olive trees can also be planted in the garden.
Planting and care
Olives are among the most undemanding container plants. They are best planted in stable pots in high-quality potted plant soil. Clay or terracotta pots work well as they evaporate excess moisture. The drought-loving plants should only be watered sparingly, because olive trees are very sensitive to waterlogging. For better water drainage, it is best to put a ten centimeter high layer of expanded clay on the bottom of the pot when planting. Since olive trees prefer a nutrient-poor soil, it is sufficient if you treat them to high-quality container plant fertilizer once or twice a month. Repotting is hardly necessary because of the slow growth.
Plant out the olive tree
Planting an olive tree in the garden is only possible in very mild winter areas. In the open field, the olive tree absolutely needs a sheltered, sunny place with plenty of space around the roots and crown. Since olive trees are very sensitive to frost, only older (but not too old!) Specimens of hardy varieties that were grown in local tree nurseries are suitable for planting. Be careful when importing older trees from southern Europe! These plants, which are used to the warm climate, usually cannot tolerate the temperature change. Even when planting outdoors, a drainage made of gravel or expanded clay should be installed in the planting hole to avoid waterlogging. Cover the entire root ball with soil and support the newly planted olive tree with a support post. Tip: A good compromise is to dig a not too big olive tree in the garden over the summer together with the plant pot. In this way, the tree can be removed from the bed again in autumn and safely overwintered.
For us, olives are primarily ornamental plants that should stay in good shape. Since the Mediterranean trees grow naturally very light and have wide spacing between leaves, the trees are best grown as tall trunks with a dense crown. Therefore, shorten the branches two to three times a year. The long, thin shoots that the container plant formed before the winter break should be brought into the desired shape in February / March. How to grow an olive tree trunk with a dense crown:
1st year: Cut the main shoot of the olive tree to the desired height and shorten or remove the side branches.
2nd year: Continue to remove the lowest shoots directly on the trunk, regularly prune the upper ones to encourage branching.
5th year: after a few years a dense crown develops. Always shorten the shoots just above a pair of leaves.
Frequent pruning allows olives to grow more densely, and the trees can also tolerate radical pruning.
Winter protection and overwintering
As tolerant as olive trees are to extreme heat, they are sensitive to frost. Sun worshipers react extremely drastically to sub-zero temperatures, and harsh winters can completely destroy even old trees. For this reason, olive trees are placed in bright winter quarters at night temperatures of around five degrees in autumn, which are five to eight degrees cool. This can be the hallway, but also a well-insulated greenhouse or an unheated winter garden. The winter quarters for olive trees can also be dark in an emergency, but the plant then sheds all leaves, but sprouts again in spring. If the temperatures are above ten degrees, the bloom and fruit formation suffer in the long run. In winter, olives are poured just enough to prevent the bale from drying out, but as evenly as possible. From April / May the potted plants are allowed to go outside again. Older, planted specimens require “full-body winter protection”. Before the first frost, wrap both the treetop and the trunk in several layers of fleece and cover the tree slice with sticks or leaves.
The olive tree is propagated by cuttings. To do this, cut an approximately ten centimeter long piece from a young, not lignified shoot at an angle with a sharp knife. When making your selection, make sure that eyes are already laid on the cutting. Then remove the lower leaves, press the stem in rooting powder, and place the mini olive in a bowl or pot of potting soil. Lightly water the cuttings and place them in a bright, warm place at at least 20 degrees. Keep evenly moist for the next few weeks, then the first new leaflets will soon sprout.
With its incredibly long cultural history, it is only understandable that there are now thousands of more or less different types of olives around the world. Most of the varieties come from Spain, Italy, Greece and North Africa. If you only want a single olive tree but like to harvest olives, you should choose a self-fruiting variety. These are, for example, ‘Frantoio’, ‘Pendolino’, Itrana ’,‘ Leccio ’and‘ Cailletier ’. If you are thinking of planting your olive tree in your garden after a few years of acclimatization, you should go for a conditionally frost-hardy variety such as ‘Arbequina’, ‘Lessini’, ‘Cornicabra’, ‘Ascolana’, ‘Picual’ from the outset, even in a mild region ‘,’ Leccino ‘,’ Hojiblanca ‘or’ Empeltre ‘. The ‘Aglandou’ variety from the south of France, like the Italian ucht Frantoio ’variety, combines self-fertility with frost tolerance.
Diseases and pests
In spring, the young shoots attract aphids. Brown bumps on leaves and on the petioles indicate scale insects. Woolly webs in the leaf axils and on the underside of the leaf indicate mealybugs. If the earth dries out too much, the tree sheds its leaves. Warning: olives react with a delay and can resent care errors weeks later.
Frequently Asked Questions
Which soil is suitable for the olive tree?
The olive tree can cope with normal potted plant soil.
How often do you have to water an olive tree?
Since the olive tree is a very drought-loving plant, it should only be watered sparingly. In addition, one should make sure that no waterlogging occurs, because the olive tree is particularly sensitive to this.
Which fertilizer is suitable for an olive tree?
It is best to fertilize the olive tree with a high-quality container plant fertilizer. It is usually sufficient to fertilize it once or twice a month, as it naturally prefers a nutrient-poor soil.
How can you overwinter an olive tree?
The best way to overwinter the olive tree in the pot is in a light, five to eight degrees Celsius warm winter quarters. Alternatively, the winter quarters can also be dark, but the olive tree then sheds its leaves. But don’t worry: the leaves will sprout again in spring. If, on the other hand, the tree is planted out, it needs winter protection consisting of several layers of fleece. In addition, you should cover the tree slice with brushwood or leaves.
When can the olive tree go outside?
After wintering, the olive tree can go outside again from April / May.
When can you prune an olive tree?
If you want to cut your olive tree, it is best to wait until spring after it has been wintered.