Q.Lime Tree in My Neighbour’s Garden
This is approximately 10 feet tall and has what appears to be lime size fruit on it. It has a white blossom in spring, but then forming on the leaves it has a sticky leaf substance, which appears to be very attractive to bees and wasps on a continuous bases. Also seems particularly favorable to small birds, such as goldfinches and green finches.
All citrus trees have fruit that looks like a lime when it starts fruiting. You won't be able to tell what type of tree it is until the fruit ripens. You could always ask your neighbor about it. Also the sticky substance is sap, and birds and bugs really do love it.