Olive (Olea europaea)

Olive picking

Over the past few weeks the olives on my tree (Kent, England) have been ripening from green to black. As soon as they go black I've been picking them. I've managed to fill three 500ml Le Parfait (Kilner-type) jars so far. I've had more this year than before. I suspect it is because of the previous hard winter although I'm not absolutely sure. I've tried picking and curing the green (unripe) olives but they didn't taste as good so I'm only using the ripe black ones from now on.

Olive tree (Olea europaea)

Curing olives

Olives are better after being soaked to remove the bitterness caused by the presence of oleuropein. There are many ways of doing this. I soak them in plain water (or salt water) or pack them in sea salt until the bitterness leaches out. Making a long cut in flesh of the olive down to the stone is supposed to help. I never did this with mine but might try it this year.

Storing olives
The olives can then be used immediately or stored for a short period in plain water or olive oil in the fridge. For long term storage, place olives in an sterilised airtight jar and cover with salt water or olive oil. You can add garlic, slices of lemon or herbs for additional flavour. They should keep for up to a year like this. Mine get eaten quickly so never last that long.

Olives in the British Isles

Olive trees are traditionally from the Mediterranean but are quite hardy and do well in the British Isles. I've had my olive tree for around ten years and it has tolerated temperatures down to -8°C with heavy snowfall although it didn't like it overly much. In fact it lost a lot of leaves that winter (2010/11) and took a year or two to recover. I've pruned it so that it sits less than 3 metres high. Olive trees do well planted in a southerly or westerly facing position, perhaps up against a warm wall and with some protection from cold winds. They don't like to stand in waterlogged soil and they do better in a soil rich in calcium or limestone. Some reports say that olive trees thrive on neglect but mine liked a bit of food and water. I put a few buckets of rich homemade compost around the base each spring or summer. 

Pruning olives trees

If you want to prune an olive tree do so lightly in the spring or more vigorously during the summer so the tree has time to recover before winter sets in. Don't prune in the autumn if you can help it and not at all in winter. Excessive pruning will reduce the likelihood of a bumper crop of olives. What I love about olive trees are the fact that they are evergreen but have lovely light green sparkly leaves. These will give you privacy but won't cut out the light like the dark leaves of a Bay tree would.

Pollination

Most olive trees are self fertile but having more than one tree will increase cross pollination and help bump up olive numbers. I've just bought another two trees which I hope will do this. I'm going to put one in a more exposed position in the front garden to see if it thrives in more exposed conditions. Some reports say that olive trees need two months of cold weather with temperatures below 10°C to kick start the flowering, and thus fruiting, process. This is generally the case in the British Isles and is not something we should be too worried about.

Pressing olive oil

Apart from preserving the olives whole, they can be pressed to make an oil. It takes around 4-5 kilos of olives to produce 1 kilo of oil. Olives need to be minced or crushed and then pressed to extract the oil. The professionals use expensive specialist equipment.

Olive leaf tea

A beneficial tea can be made out of the leaf of the olive tree. This is an easy way to take advantage of the properties of this tree and something you can do all year round because the tree is evergreen and always has an abundance of green leaves. Even if you don't get any olives, you can always use the leaves. The health benefits of olive leaves are huge and widely published. Amongst other things they are anti-bacterial, anti-viral, they soothe nervous tension and can boost the immune system.

Other uses

A dye can be made from the fruits and leaves. The wood is valuable for cabinet making and other joinery. The oil is used in cosmetics and toiletries. The olive seed can also be used to make flour and oil.

by Amanda Rofe