By Mistyp
United Kingdom 
Hi l have the same issue the olive tree in my garden has a lot of leaves turning yellow. l'm not watering it very often there a lot of olives forming .
The soil its in is clay, but l have also when l planted it out of its container followed the instructions to add John Innes no 3 this was 3 years ago.
3 Jun, 2020
Answers
I live in Evesham ,Worcester .The issue l have if l start to water the leave may all turn yellow.
3 Jun, 2020
I agree with Bamboo this is very likely due to lack of rain and it is in a clay soil despite the add JI no 3.
work a fork into the soil around the stem to open it up and give it plenty of water.
welcome to GoY too :o)
3 Jun, 2020
But if it needs water it needs it. Has it had any feed since you planted it? if not give it a general all purpose feed.
3 Jun, 2020
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