Can you please tell me what to spray on them? They are about 18 months old and nearly all of their leaves have little nibble holes in them. Please help.
It is hard to say what is eating them without you having seen the pest and being able to give a description.
That being said, neem oil is a good organic, general pesticide that only attacks pests that actually eat the plants treated with it, Just to be on the safe side, I would recommend also treating with Bt for caterpillars. Neem oil is effective on caterpillars, but Bt will be quicker. Here is more information on both:
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/plant-problems/pests/using-bacillus-thuringiensis.htm
We have a lovely fast growing Silver Princess tree which we planted about 4 years ago and yet it has never flowered or had pods on it. It meets all the ideal requirements as mentioned in your previous page. Can you offer any advice.
Have you tried a soil test? Your soil should be rich and acidic and well-draining with a pH of 7.0 or below. You can use rhododendron/azalea fertilizer. This plant does best in Zones 9 - 11, which are described in this article:
https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-9-10-11/plants-zones-9-11.htm
Here's an article with tips for general care of your plant:
https://www.gardeningknowhow.com/ornamental/shrubs/princess-flower-bush/growing-princess-flower.htm