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Potted olive trees add a Mediterranean touch to any garden. This article explains how to care for potted olive trees.
Olive trees in pots: planting, pruning and fertilization
Where to place a potted olive tree
Olive trees do well in the warm, dry climate of the Mediterranean, but can also thrive in other environments, as long as they are protected from cold, wet winters. Growing an olive tree in a pot makes it easier to care for during the winter, and as a slow-growing, woody plant, it is perfect for those who want a low-maintenance, long-term addition to their garden.
Ideal location
Unlike other potted plants that can be kept indoors, olive trees prefer to be outdoors and enjoy fresh air all year round. Indoors, they tend to lose their leaves due to lack of sunlight. Therefore, as soon as the weather gets hot in summer, it is time to take the olive tree outside. Choose a sunny spot that is not too exposed to the wind, whether in the garden, on the balcony or on the terrace. Turn the pot regularly so that all the branches get enough sun. During the winter, protect the olive tree from extreme cold, but avoid keeping it in a warm house, as some exposure to cold is important for its normal development.
Type of soil
The soil is essential for the healthy development of a potted olive tree. It needs a permeable and well-structured soil. A mixture of garden soil with potting soil, clay granules and sand is ideal.
Caring for an olive tree in a pot
It is essential to take good care of olive trees, especially those in pots, to avoid pests and diseases. If you follow these steps, your olive tree will bring you joy for many years to come.
- Irrigation: Water occasionally, allowing the soil surface to dry between waterings. Avoid waterlogging.
- Fertilization: Begin fertilizing in the second year, from March to August, applying liquid fertilizer every two weeks during watering. Use long-lasting granular fertilizer when transplanting.
- Transplant: Repot regularly: young plants approximately every two years and older plants every five years. If your tree is too big to repot, the choice of substrate and good fertilisation are even more important.
- Pruning: Prune in spring. To avoid waterlogging and root rot, only use pots with a drainage hole and place a layer of gravel or clay shards in the bottom of the pot to ensure good drainage. Place the pot on a stand to prevent direct contact with the soil.
Pruning olive trees in pots
Olive trees can be pruned as trees or shrubs. Young plants grow in a sparse manner and should be pruned more frequently to encourage branching and the formation of a dense crown. Once the olive tree has reached the desired shape, only maintenance pruning is required. Cut back shoots that are too long to a side shoot or to their origin on a stronger branch. Also remove branches that cross, prioritising the weaker ones. This is especially important for the interior of the crown or shrub, as olive trees should not grow too dense.
Use: You can drastically prune old, healthy olive trees to encourage new, rejuvenated growth. Light pruning can be done at any time of year, but more radical pruning should be reserved for spring. After the winter rest, the tree will have plenty of energy to develop vigorous new shoots.
Transplanting olive trees
Potted olive trees take a long time to grow, especially if they are not repotted regularly. For fast growth, repot once a year at first and then every 2 to 3 years in a high-quality soil. You know it’s time to repot when you see the tree’s roots poking out of the bottom of the pot. If you don’t invest in good soil, your olive tree will be more susceptible to pests, disease, and growth depression. The best soil for potted olive trees is textured, not too nutrient-rich, and well-draining. Olive trees prefer a pH between 7 and 8; if your soil is acidic, improve it with a little garden lime.
Hibernation of olive trees in pots
Olive trees are not completely cold-hardy in many regions. A frosty night doesn’t affect them much, but prolonged periods of frost and cold, wet winters can be too much for these Mediterranean trees. It’s crucial to protect them properly during the winter. Wrap the pot in newspaper or plastic bubble wrap and place it in a sheltered, frost-free but well-lit location.
Do not store them in a heated house.
They need temperatures around freezing to recognize winter, building up strength to bud and flower in spring. During winter, no fertilization is needed and watering should be occasional. Take the trees out again when no more long periods of frost are expected, usually in late March. However, keep a protective jute bag on hand in case further frost is forecast.
Buying a potted olive tree: what to look for
Olive trees bring a Mediterranean flair to gardens, making them increasingly popular. Because of this, many garden centres, DIY stores and online plant shops sell them. However, quality can vary considerably from source to source. To be on the safe side, buy your olive tree from a nursery specialising in Mediterranean trees. Choose a more cold-tolerant variety from a northern Mediterranean region.
Advice: Avoid sellers who advertise trees as completely winter-hardy, as this information is probably not true and may indicate that the seller is not trustworthy. Especially in the first year after purchase, provide good winter protection and be careful not to test the typical cold hardiness of your olive variety to the limit. In late summer, it is a good idea to provide plenty of potassium to prepare your plant for winter, for example with a liquid citrus food that is also perfect for Mediterranean plants.
How and when to fertilize
For the olive tree to develop its characteristic Mediterranean air, it needs proper care, and a crucial aspect is fertilization at the right time with the right fertilizer.
When to fertilize
Only fertilize olive trees during the growing season, from April to September. During hibernation, they do not need fertilization. Repot olive trees every few years into fresh, nutrient-rich compost, such as an all-purpose organic compost, which contains plenty of organic matter and essential nutrients for a healthy olive tree. You can amend the compost with 20% horticultural sand or gravel to improve drainage. Fertilizing is not necessary for the first few months after repotting, unless deficiency symptoms appear.
Young olive trees
Young olive trees up to two years old require very little, if any, fertilization. In this case, use a quarter or a third of the recommended dose of fertilizer. Do not fertilize olive tree seedlings and cuttings.
Recognition of deficiencies
Even the hardy olive tree can suffer from nutrient deficiencies. Here’s how to recognize nitrogen, potassium, calcium and phosphorus deficiencies, as well as their possible causes:
- Nitrogen deficiency: the leaves turn yellow and growth is very limited. This can occur if the olive tree has not been transplanted or fertilized for some time.
- Potassium deficiency: causes the tips of the leaves to dry out and eventually die.
- Calcium deficiency: Soil pH should be between 7 and 8. A calcium deficiency can occur if the pH is too low, causing yellowing of the leaves from the tips.
- Phosphorus deficiency: It appears as a reddish discoloration of the leaves, but is extremely rare.
Fertilizing olive trees: what to use and how much
Specialized fertilizers for olive and citrus trees have an optimal nutrient composition for Mediterranean plants. If you do not want to buy a specialized fertilizer, use a balanced fertilizer with nitrogen and potassium, and, ideally, other micronutrients.
Use of organic fertilizers
Organic fertilizers are beneficial for olive trees as their nutrients are stored in the soil and released gradually. Fertilizers with high organic matter content, such as liquid citrus feeds, have a gentle action and benefit soil life, as well as reducing the risk of over-fertilization. Apply liquid feed every two weeks by mixing 15 to 25 ml with 5
liters of water and water the olive tree as needed.
Use of mineral fertilizers
If the olive tree suffers from a severe nitrogen deficiency, mineral fertilizers can quickly solve the problem. However, their continuous use is not recommended due to the high risk of over-fertilization and the negative environmental impact.
Home remedies
Coffee grounds are a nitrogen-rich waste product that can be used as fertilizer, although they can acidify the soil. You can also use herbal teas such as nettle slurry to provide additional nutrients and combat pests.
Recognition of over fertilization
Over-fertilization is more dangerous than deficiency. Symptoms include scorched leaves with yellow or brown edges and curled leaves. In case of over-fertilization, repot the olive tree in fresh compost to remedy the problem.
Transplanting olive trees: when and how
Transplanting olive trees is essential for their optimal growth. It is recommended to transplant for the first time just after purchase and then every 2 to 3 years. The best time to transplant is in late winter or early spring.
Step-by-step guide to transplanting
- Lay the olive tree on its side.
- Release the root ball from the pot by twisting and pulling.
- Removes dead fine roots and weeds.
- Place a drainage layer in the bottom of the new pot.
- Fill the new pot 20-30% with soil and press down lightly.
- Place the olive tree and fill the spaces with soil.
- Press firmly and water well.
Do not fertilize the olive tree for six weeks after transplanting, as the new soil contains enough nutrients for this period.
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