This mature olive tree has developed a good crown featuring vigorous growth and healthy colour. Age: Approx 19 yearsOverall height inc. pot: 220cmMain Tunk height: 39cmPot size: 35ltrPot height: 35cm
Short Mature Olive Tree
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. A 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, potting up with a mixture of John Innes No.3 and multipurpose compost, ideally with some added grit for drainage.
To help promote new growth, flowering and fruiting, give a feed with a slow release general purpose fertiliser around the base of the plant in spring. In the growing season an occasional feed with a liquid fertiliser is beneficial. Stop feeding after August as this will promote soft new growth which could be damaged in winter. It is more important to feed container planted trees as the nutrients are soon depleted from the soil after a growing season.
Pruning is simple! The important thing 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. In the UK we are less concerned about open centre as Olive fruit is not the priority in the UK. The message is to prune the Olive tree in order to produce a crown to suit your space. There is no science to pruning a tree outside of the 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!
If planted into a container make sure the tree is well watered during the growing season as the roots cannot search for water like they do in the ground, especially so if in terracotta as this bakes the soil in summer. In the first year of planting, olive trees in the ground need to be kept well watered too, however once established they can tolerate some small periods of drought but prefer to be watered occasionally.
Generally pest free, occasionally olive trees can be prone to Peacock or Black Spot or Woolly Aphid. Black Spot (small brown circles on leaf, leaf turning yellowy brown) can be treated by spraying with a fungicide. Woolly Aphid (white fluffy like substance appearing on leaf axils and pruning cuts) needs treating with an insecticide. Follow manufacturer’s instructions for best application.
Olive trees are surprisingly very hardy; large plants can be hardy to around -15C (and lower), as long as the compost/soil is well drained. Mature plants will be evergreen to around this temperature, younger plants are more susceptible to leaf loss if the temperatures are continually very low. Small plants can be over-wintered inside to help retain leaves; maximise ventilation and light and water occasionally. They soon start to regain their leaves once the spring has arrived. Watch out for the roots of containerised plants becoming waterlogged.
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 inwhich to under-plant with a herbs for example. After one season, the sleepers ‘silver’ providing a super and cost effective planter.
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.