The Olive Tree as Bonsai
HEART OF THE MEDITERRANEAN - THE OLIVE TREE
Prior to cheap airfares very few of us in Blighty would have been capable of identifying an olive tree. Today most folk with even a small interest in arboricultural matters will recount tales of being impressed by the ancient olive trees of some exotic sounding Mediterranean destination. In U.K bonsai circles good quality olive trees have been practically unobtainable until fairly recently….but who would have the heart to remove a lovely olive tree from its sun kissed home on some romantic foreign shore and bring it back to suffer the rigours of a dark wet English winter??
Silly romantic notions aside it is testament to the olive's adaptability and determination that, in spite of what you may have read, it does grow very well here. Before going any further please let me point out that what follows is based on my own experience of cultivating olive trees as bonsai in the U.K. It is 5 years since I bought my first olive tree, he is doing very well and should be on exhibition at a major show next year. I live on the Norfolk/Suffolk border just four miles from the sea. Here the weather is fairly mild. The spring time is generally a little cooler than many places but the autumn time is warmer. Winter nights are usually a few degrees warmer than further inland thanks to the warming effect of the sea. We are in what's termed a rain shadow area so the climate is perhaps a little drier than much of the U.K although who knew this year!!
There is a myth in bonsai circles that olive trees are not hardy. This seems to be the main concern I have encountered in talking to people about this species. Much mis-information probably stems from the fact that a lot of little olive trees have come from China and other places to be sold as Indoor Bonsai. I have seen more than one book stating that olives are not hardy but do make ideal Indoor Bonsai. "Google" Olive trees and you will get about 2.75 million hits. It won't take you long to find out that these plants are indeed hardy…very hardy! For good fruit production the trees should not be exposed to temperatures lower than -5 Celsius. However the trees will stand much lower temperatures with little damage. My own olive's have remained outside to -8 Celsius whilst exposed to freezing winds with absolutely no adverse effects whatsoever.
Olea is a genus of about 20 species in the family Oleaceae, native to warm temperate and tropical regions of southern Europe, Africa, southern Asia and Australasia. They are evergreen trees and shrubs, with small, opposite, entire leaves. The fruit is called a drupe. There are literally hundreds of cultivars of olive tree. Much like apples, trees with different fruit characteristics have been developed over hundreds of years. The species is very variable and no two tree ever seem to be quite the same. As far as bonsai is concerned we are going to encounter three main groups where the foliage is the defining characteristic.
Olea oleaster, a wild olive whose cultivar "Olivastro" is used as rootstock for O. europaea; formerly classified as the subspecies O. europaea oleaster. By far the best type for bonsai cultivation. Tiny leaves, vertical growing twigs when mature. Good examples will have spectacular bark and natural deadwood. Generally collected from the wild in costal regions. Extremely vigorous and forgiving. Most expensive but this is the one to buy!
Olea sylvestris, a small-fruited wild olive of the Mediterranean region. Medium size dark green shiny leaves generally more rounded than oleaster. Looser growing habit. More susceptible to fungal problems in very damp conditions.
Olea europaea, the primary type of olive cultivated for fruit production. Most come from old olive groves. Large oblong grey leaves, very loose habit. Tolerant of most conditions. Good quality bark is rare with this type. Big cheap trees are often available in general nurseries and garden centres.
CULTIVATING OLIVES IN THE U.K SOIL
My experience of growing this tree has been very rewarding. Olives are a tree that really 'wants' to grow. All we have to do is give it what it needs for success. In spite of the difference between it's natural habitat and the U.K it will adapt and settle into life here in just one good growing season.
As already stated cold is not our worst enemy as far as olives are concerned. The big problem is the combination of cold AND wet. The effects of which can be just too much for these great trees to handle. As they say 'the secret is in the soil'. Heavy wet cold soil will be the undoing of this species. I would suggest using a mix of 75-25% grey pumice to akadama or 50-35-15 Moler (biosorb), Pine bark chips, akadama. Its imperative to bare root the trees when re-potting. Re-pot every third or fourth year in late spring. If your tree suffers a massive leaf drop in winter it's going to be down to wet soil.
In spite of growing in impoverished soil in the wild olive trees in cultivation appreciate a regular programme of feeding. If using the soil mix detailed above it's important to use some organic fertiliser both for the tree and the bacteria in the soil. Either Green Dream or Bio-Gold is ideal for this. Many folk are using chicken manure but I do not recommend it in this case, it is very weak and not balanced or fortified with micro nutrients or trace elements. Covering the soil surface with a layer of chicken manure will quickly clog the soil and destroy your drainage. So, use a little good quality organic feed regularly. Alongside this use at regular strength a good chemical feed like Chempak No3 EVERY WEEK from March to early November.
Olives grow quickly in spring and summer, because of this wiring is best carried out in autumn. Conventional pruning techniques of cutting to twos in order to increase ramification is important. Many olives have poor branch structure formed from straight thick branches with a herring bone form beneath the foliage, this makes for a very poor quality bonsai. Olive branches fork readily so there is no excuse for poor form. Maintenance pruning is the same as any broad leaf tree.
Keep the bark of olives clean, algae and moss will quickly destroy the beautiful white colour and decay craggy bark. Always keep olives in full sun and a well aired or windy spot in the garden. Keep an eye out for black scale insects. Grey circles on the leaves followed by yellowing or the appearance of black dust like sooty mildew is the result of infection by Cycolconium oleaginum. Spray olives with Bordeaux mixture in early autumn and spring. Also do not allow the foliage to sit wet (as in a poly tunnel) for long periods of time. Good horticultural nursery practise will keep olives free of problems.
Apart from that just enjoy keeping these fascinating trees, they make beautiful bonsai trees.
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FOLKLORE AND HISTORY
The olive tree has been the symbol of wisdom and peace. The olive tree was the sacred tree of goddess Athena and Athens, the capital of Greece, took its name from the goddess. Zeus had decreed that the city should be given to the god who offered the most useful gift to the people. Poseidon gave them the horse. Athena struck the bare soil with her spear and caused an olive tree to spring up. The people were so delighted with the olive that Zeus gave the city to Athena and named it after her. Athena is often shown with an olive branch, a symbol of peace and plenty.
At the Ancient Olympic Games, winners were presented with a simple olive tree branch which was cut with a gold-handled knife from a wild olive tree. The Greeks believed that the vitality of the sacred tree was transmitted to the recipient through the branch.
The olive oil is still being used for medical purposes and religious purposes and it has been proved to be an essential ingredient of a healthy diet. As a monosaturated fatty acid, olive oil does not have the same cholesterol-raising effect of saturated fats. Olive oil is also a good source of antioxidants. Olive oil, unlike seed oils, remains stable in its chemical structure at relatively high temperatures because of its antioxidant and high oleic acid content.
First olive press in the world was found on the island of Crete around 1600 B.C.
- Homer in the "Odyssey" refers to olive oil as "liquid gold"
- Solon's Olive protection Law during the Athenian democracy (600 B.C.), in the first written legislation of the world, prohibited the cutting down of olive trees
- Olympic games winners in ancient Greece were crowned with olive branches
- Greek Orthodox rituals such as christenings & blessings use olive oil
- In Genesis, a dove released from the Ark by Noah, returned with an olive branch to show that the flood had receded.
- Hercules was protected by wearing a wreath of olive leaves upon his head
- For bravery in battle, Roman soldiers were rewarded with crowns of olive
- Nobel prize winner Greek poet Odysseas Elytis wrote "Greece is a vine, an olive tree and a boat"
- Thomas Jefferson wrote: "The olive tree is surely the richest gift of Heaven"
- Aldous Huxley wrote: "…I like them all, but especially the olive. For what it symbolizes, first of all, peace with its leaves and joy with its golden oil."
- Federico Garcia Lorca wrote: "Angels with long braids and hearts of olive oil."
- Lawrence Durrell wrote in Prospero's Cell, "The entire Mediterranean seems to rise out of the sour, pungent taste of black olives between the teeth. A taste older than meat or wine, a taste as old as cold water. Only the sea itself seems as ancient a part of the region as the olive and its oil, that like no other products of nature, have shaped civilizations from remotest antiquity to the present."
© Kaizen Bonsai Ltd 01/2008