The first thing to remember is that Olive trees really hate to have wet feet, so make sure that if you have planted yours in a pot there is a large amount of drainage. If in ground make sure it’s in free draining ground and not a waterlogged or boggy area.
I regularly find that one of peoples biggest mistakes is thinking that Olive trees are drought resistant believing that they do not need watering. It is easy to assume when you see them in Greece where it’s million and one degrees growing away happily, looking like they are the happiest plants of all (they probably are too). It is easy to forget that those wild trees have enormous root systems stretching away under that dusty hard baked ground which gives them an incredible life support.
When the olives you can buy from us are lifted from that ground the root is massively reduced which in turn makes the plants life support heavily reduced. The tree now ultimately relies on what you give it, this goes for both food and water alike.
There is, unfortunately, no precise amount of water as we have this wonderful variable thing called 'The British Weather' which forces us to use the saying ‘How Longs A Piece Of String?’ almost constantly. Obliviously through the winter watering isn’t normally necessary as mother nature tends to gives us a fare whack of the wet stuff. Spring, Summer and Autumn (aka most of the year) are the ones you need to watch.
Through a dry spell (more than a week or so) we would be putting around 7-10ltrs a day onto an olive with a root ball (pot size) of 60-80cm diameter where as a pot 30-40cm would likely need 4-5ltrs.
This amount is reduced when its cooler to every other day and then again to every 3 days when its coming on cold. Be careful watering in the winter when it is actually freezing, I do not recommend to douse things with water when they are frozen hard, instead wait for it to thaw and check it to see how wet it might be.
If there is a odd rain shower please don’t think that’s enough, is is unlikely to have been enough for it to have permeated much below the first half inch, so it still will need watering if we are lucky enough for it to be on the warmer side.
Feed in March and then again mid to late August with Vitax Q4
Trimming and Pruning
Trimming can be done all year round so long as you are leaving plenty of foliage on the plant.
If you are doing a hard prune (which is perfectly alright, we have this video here of me quite literally cutting the top off an olive here) that will leave it pretty, or even completely bare, I would recommend doing it in early March at the same time as you feed it. If the weather is still goodly cold in March just hold off until April.
You really can prune them as hard as you like, they will grow back! Don’t panic if it takes a while to shoot It can take anywhere up to 6 weeks or more or the plant to get going again.
Once you get the 'feel' of how to look after your Olea (Olive) it will become second nature. Just remember, they don't like being to wet... or too dry, well for too long at least...