Let me start by saying one thing, olive trees are very robust and they can handle a wide range of extremes.
All of my olive trees are grown outdoors rather than in tunnels and this means that from a young age they are accustomed to changes in the natural environment around them.
However, whilst they are hardy, there are still some basic steps you need to take to ensure a happy tree! Here is a simple guide to help you look after yours..
Olive trees love a sunny, sheltered, well drained site... a south facing position is ideal, however it’s not essential as long as there is lots of sunlight and the soil is well drained. Well drained soil can be achieved by digging in lots of grit before planting. Wind is not a problem for olives - they can even cope in a seaside location with salt laden winds. The same conditions apply for container grown olives.
If the tree in planted in the ground, after initial watering for the first growing season, the Olive tree will be completely drought tolerant.
If the Olive trees are displayed in containers, the trees roots are not able to find water other than the water we or nature add. Rain falling onto a pot surface provides little benefit. It is important to keep the Olive trees watered during their growing season when in containers, and ensure they do not dry out completely during the winter. No plant on this planet can live without any water!
Olive Trees will grow at their best in a normal top soil. Drainage is the main criteria for a happy health Olive Tree. Top soil and compost mix can be used; however, soil holds moisture much better than compost.
Good drainage can be acquired by using crocks and broken bricks/stones in the bottom of a pot/hole. The use of a French drain can also help if you are planting into poorly drained soil.
Pruning - Late Spring / Early Summer
Pruning is very simple and as olive trees grow slowly, you won’t need to prune them all that regularly.
Any pruning should be conducted after the last frost has passed, in late spring or early summer. This allows your tree to heal, so as not to leave ‘wounds’ open in the colder months which can be particularly damaging.
The idea is to keep the tree pruned back each year to encourage good leaf growth. Imagine a single shoot, pruned. At the point where you prune the shoot, two or three new shoots will spur, which means the shoot suddenly becomes a multi-shoot. Imagine pruning 100 shoots all over the tree to produce 300 new shoots. This is how you develop the crown.
There is no science to pruning a tree outside of a commercial environment and the Olive trees do not suffer from die back. This means you can prune anywhere and not worry about pruning just above a shoot.
Remember that if you do not prune the tree, then the single shoots will continue to head for the skies. As the shoot matures and thickens into a branch, the mature wood stops producing leaves. If you have seen an Olive tree with all the leaves on the outer branches, and looking rather thin and woody in the centre, then this is the reason!
It is recommended that you cut back shoots which grow from the base of the trunk upwards, as these can affect how much energy the tree puts into growing. Removing these encourages the tree to place its focus on growing the crown of the plant.
Olive trees survive with little nutrients, but again, if the tree is in a container, provide it with a ‘tonic’ of Tomato food in May as the tree is waking up and then again every 6 weeks through the growing period.
It is not essential but growers have found this to be a benefit to the tree.
Rule No. 1 / Do not let your potted Olive tree dry out in Winter.
The roots of an Olive tree can withstand being deep frozen for 2 weeks, providing the tree was hydrated prior to the freeze. Turning this around, trees that are dry suffer more than the trees which were watered. During these extreme in low temperatures, it has been observed that ‘dry’ trees suffered frost damage into the main branches and occasionally into the trunk, whereas the hydrated trees suffered less.
A good hard prune the following spring encouraged the trees to bounce back.
Rule No. 2 / Position away from the elements.
While olive trees are able to cope with temperatures that are -10 Celsius and above, cold harsh winds can be damaging.
Once it starts getting low it wont be a bad idea to cover with horticultural fleece. The goal here is to avoid condensation touching the plant since it is a source of excess moisture. Expect this period to be around December to February.
Moving your tree to a more sheltered position will also reduce wind and excess moisture from the rain.
Pests & Disease
Often the leaves of an Olive trees appear ‘nibbled’. This is caused by a leaf beetle and is nothing to be concerned about. It is not detrimental to the trees health and hardly noticeable.
Peacock spot on Olive trees becomes apparent after wet winters and continued wet springs. It is not serious unless you are in the business of harvesting fruit on a large scale. Peacock spot, however, should be treated if possible to maintain good leaf cover and avoid excessive leaf drop. Peacock spot can be treated with a copper solution, preferably after a long dry period (easier said than done this Spring!).
Mealy Bugs – now these are a pain, especially if the trees are indoors. It is easier to remove this pest by detecting it early. Look for white ‘fluffy’ powder under the leaves and at the leaf axis. The ‘bug’ operates by sucking the sap from the trees (not only olive trees but any plants that are placed indoors). They can be blasted off with a stream of water or a cloth with Alcohol can be used to wipe of the pest. Soap solution also works and it effectively suffocates the little pests.
Olive trees will bounce back from most things. Even if the tree loses all it’s leaves, with a little care, the tree will be back and flourishing in no time.
Planting in pots...
Olive trees do extremely well in pots and can cope with being pot bound providing the crowns is kept cropped and in shape. You must also remember to water your Olive trees more frequently when in pots. Consider building a simple bottomless box around the base of your trees. This can be simply done using new sleepers (not old contaminated railway sleepers), purchased from your local builders merchant. They are cost effective and easy to cut and put together creating a very attractive container. Make the sleeper container as large as you wish in order to balance the crown of the Olive trees. This also provides soil areas in which to under-plant with a herbs for example. After one season, the sleepers ‘silver’ providing a super and cost effective planter.
Planting directly into the ground...
Olive trees thrive when planted directly into the ground. They prefer alkaline soils and are happiest in poor soils, sandy, gravel types and chalk. They are also fine in any free draining soil. The trees also grown well in clay, however, our wet UK climate means if you have clay soils, you should consider how long it takes for the water to drain. This is easy to test, as you simply need to dig a hole, fill it with water, and see how quickly the water drains away. If it is still full of water after a few hours then imagine the roots of the Olive tree during the winter, probably too wet. You can help this problem, by only half planting the root-ball and then grading a more free draining soil from the existing ground level to the top of the Olive tree root-ball. If you choose to plant this graded soil with lavender, for example, then the tree will appear natural. Only part planting the Olive tree also means you retain some height so the Olive tree is viewed and enjoyed even more.
Can I keep an Olive Tree indoors?
Given enough light and the correct watering, olive trees thrive indoors. Large olive trees look fantastic in hotels, restaurants, shops and offices. Stunning in art galleries, and make a lovely backdrop to shopping malls. Olive trees make glorious container trees for the home.
I hope you have found some use in this guide. If you ever have any questions then please do not hesitate to get in touch.