why hasn't my mock orange flowered?

If its the yellow form they really struggle to produce even a few flowers. sometimes too much fertilizer could be the problem but Im assuming your feeding them all the same

Pruning them after flowering not only keeps the shape of the shrub, but stimulates new shoots which will produce the flowers next year. Maybe you could trim the non-flowering one in July with the others after the normal flowering period, and see if it helps for next year.

3 years ago when i moved here the mock orange was full of flowers. It then recieved a huge haircut from my mum that was visiting and didnt do anything the following year. This year however it has loads of flower buds, and not much black fly as I also remember it having lots last year.

You could google Lepidoptera Breeders Asscociation, they use Citrus species to raise butterflies and moths.

dear treesandthings