A few days ago I was walking near our daughter's house when I came across a stand of plants by the side of the road that I had never seen before anywhere on the island. Their sky blue flowers really stood out. Closer inspection and research showed them to be Phacelia tanecetifolia, native to south-western USA and north-west Mexico. Apparently they are often used as an attractant for bees and other pollinating insects. Our daughter then remembered that the man who lived in the house adjacent to where the flowers were until 2 years ago used to keep bees.
Further research showed that they are regarded as naturalised in a small area of the Troodos Range between 800 and 1,000 metres. As this location is nowhere near the Troodos, or that altitude, it remains a mystery how they have escaped notice until now.