Flowering time (month)
Ornamental or utility value
neutral to slightly acidic
With an olive tree (Olea europaea), or real olive tree, you get the dream of the sunny south on your own terrace. The Mediterranean plant belongs to the olive family (Oleaceae) and has been cultivated since the fourth millennium B.C. – not only in the Mediterranean, but also in the Middle East and Africa. This makes it one of the oldest known useful plants of all. With its silver-grey foliage, the olive tree is characteristic of the Mediterranean and has a strong symbolism. Already in ancient times olive leaves stood as a sign for peace. A wreath of olive branches was considered the highest award at the Olympic Games.
The Mediterranean plant is very slow-growing, but can grow up to 20 metres high in its Mediterranean homeland over the decades. In the tub, however, the olive tree reaches a maximum of 1.50 metres. Olive trees become very old in nature. There are some specimens known that have 1,000 years and more on their backs. The smooth, silvery-green bark of the trees changes with increasing age to a cracked bark. Olive trees gain a lot of aesthetic radiance over the years. The older the trees are, the more picturesque they present themselves.
Olive trees bear characteristic narrow leaves, dark green on the top and silvery grey on the bottom. The shimmering colour is created by a fine coat of hair, which reduces the evaporation of water from the tree and thus protects it from drying out. The leaves are alternate and stand on short stems.
The grape-like yellowish-white flowers of the olive trees appear in May and exude a delicate fragrance. They stand on two to four centimeter long panicles, but are rather inconspicuous overall. Attention: Olives usually do not flower until they are four to six years old, the first fruits develop from about the seventh year.
The fruits of the olive tree are oval and change colour from green to brownish to black as they ripen. In the middle is a large seed. Olives cannot be eaten raw, they must be cooked or pickled. A second tree as pollination partner is advantageous so that fruit ripens from the blossoms, because foreign pollination increases the harvest yield. For the home garden there are also a number of self-fertile varieties which flower reliably and bear fruit annually. As they grow older, the trees become more productive, yielding a good harvest only every other year.
Location and substrate
Olive trees love sunny, warm to hot places and are therefore suitable for balconies and terraces facing south as well as the cold and temperate winter garden. The silver-grey potted plant is particularly effective in terracotta pots in combination with roses, oleander, lead root or mallow. Because it only grows slowly and requires 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 tub plants of all. They are best planted in sturdy pots in high-quality pot plant soil. Clay or terracotta pots are well suited as they evaporate excess moisture. The drought-loving plants should only be watered sparingly, because olive trees react very sensitively to waterlogging. For better water drainage, it is best to apply a layer of expanded clay about ten centimeters high to the bottom of the pot when planting. Since olive trees prefer a nutrient-poor soil, it is sufficient to give them high-quality pot plant fertilizer once or twice a month. Repotting is hardly necessary because of the slow growth.
Planting an olive tree
Planting an olive tree in the garden is only possible in very mild winter areas. In the open, the olive tree absolutely needs a wind-protected, sunny place with plenty of free space around root and crown. Since olive trees are very sensitive to frost, only older (but not too old!) hardy varieties grown in local nurseries are suitable for planting. Be careful when importing older trees from Southern Europe! These plants, which are accustomed to the warm climate, usually do not tolerate the temperature change. When planting outdoors, a gravel or expanded clay drainage system should also be installed in the planting hole to prevent 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 bury a not too big olive tree in the garden during the summer together with the plant pot. In this way the little tree can be removed from the bed again in autumn and wintered safely.
Our olives are first and foremost ornamental plants that should stay in good shape. Since the Mediterranean shrubs grow very light by nature and show wide leaf distances, the trees are best cultivated as tall stems with a dense crown. You should therefore shorten the branches two to three times a year. The long, thin shoots that the tub plant has 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 stem of the olive tree at the desired height and shorten or remove the side branches.2nd year: Continue to remove the lowest shoots directly from the trunk, the upper ones regularly prick to promote branching.5th year: After a few years, a dense crown develops. Frequent pruning makes olives grow more densely, even radical pruning is usually well tolerated by the trees. However, the harvest cannot be increased by special cutting measures.
Winter protection and overwintering
As tolerant as olive trees are to great heat, they are sensitive to frost. The sun worshippers react extremely drastically to minus temperatures, rough winters can destroy even old trees completely. This is why olive trees are placed in a bright, five to eight degree cool winter quarter at night temperatures of around five degrees Celsius in autumn. This can be the hallway, but also a well insulated greenhouse or an unheated conservatory. The winter quarters for olive trees may also be dark in an emergency, but the plant will then shed all its leaves, but will sprout again in spring. If the temperatures are above ten degrees, the formation of flowers and fruits suffers in the long run. In winter, olives are poured just enough so that the bale does not dry out, but as evenly as possible. From April/May the potted plants will be allowed outdoors again. Older, planted out specimens need a “full-body winter protection”. Before the first frost, pack both the tree crown and the trunk in several layers of fleece and cover the tree disc with brushwood or leaves.
The olive tree is propagated by cuttings. To do this, cut a piece about ten centimeters long from a young, unwoody shoot diagonally with a sharp knife. When making your selection, make sure that eyes are already attached to the cuttings. Then remove the lower leaves, press the shaft into rooting powder and place the mini olive in a bowl or pot of growing soil. Lightly water the cuttings and place in a light, warm place at a temperature of at least 20 degrees Celsius. Keep evenly moist for the next few weeks, then the first new leaves will soon sprout.
With its incredibly long cultural history, it is understandable that there are now thousands of more or less different olive varieties worldwide. Most 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-fertile variety. These are for example ‘Frantoio’, ‘Pendolino’, ‘Itrana’, ‘Leccio’ and ‘Cailletier’. If you are thinking of planting your olive tree in the garden after a few years of acclimatisation, you should also choose from the outset a hardy variety such as ‘Arbequina’, ‘Lessini’, ‘Cornicabra’, ‘Ascolana’, ‘Picual’, ‘Leccino’, ‘Hojiblanca’ or ‘Empeltre’ in a mild region. The variety ‘Aglandou’, which originates from southern France, combines self-fertility with frost tolerance, as does the Italian variety ‘Frantoio’.
Diseases and pests
In spring the young shoots attract aphids. Brown humps on leaves and petioles indicate scale insects. Woolly webs in the leaf axils and on the underside of the leaf indicate aphids. If the soil dries out too much, the tree throws off its leaves. Attention: Olives react delayed and can resent care mistakes still weeks later.
Whether potted plants such as oleanders or indoor plants such as orchids: The scale insect infests the most diverse plants. René Wadas, a herbalist, will give you his tips on pest prevention and control: Production: Folkert Siemens; Camera: Fabian Primsch; Editing: Dennis Fuhro; Photo: Flora Press/Thomas Lohrer
Olive trees in the our store-Shop
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.