grateful thanks for any answer

Does this happen every year, Jean? It could need watering, or perhaps it's not sheltered enough where it is. They need good, hot summers to flower at all, it says in my gardening book, so perhaps it's too exposed to the cold. You could try moving it, or put it in a pot and move it into the greenhouse in the winter. They also like feeding well, and a slightly alkaline soil. hope this all helps and that you get some flowers next year! We might even have a really good summer next year, and it'll flower its buds off!! Annie

Spridgen, If you add where you live to your home page it makes it easier for people to give you the best advice.
You must live somewhere very mild and sheltered to have kept it so long. If it is moveable you could try bringing it in for the winter as Anne suggests, or at least giving it a really deep mulch.

Causes for bud drop on H. syriacus include too much water, too little water, irregular watering, and too much fertilizer. To decide which of these applies, we would have to know more details, such as whether it is in a pot or the ground, what the watering schedule is, and what it is fed with, how much, and how often.

Hmmm. I'm curious about Anneashby's comment about alkaline soil. Mine was failing until I potted it up with ericacious compost, and it flowered fine after that. It is the shiny leaved tropical hibiscus.
I have, just yesterday, bought a hardy (matt leaved) hibiscus, and had planned to place it in acid compost too. Would that be wrong?

I'm curious about the mild and sheltered comment Steragram because hibiscus is a very common, freely flowering, garden shrub here in the Czech Republic where winter temps can drop to -20 and below. The hibiscus appear to be fully frost hardy. I have a white one that is happily in its fifth year, going from strength to strength - I've just looked at the photo of it in My Photos which was taken 2 years ago and am amazed at how much it has grown.

That's great Cestina, but I'm very puzzled. All the ones listed in the RHS book are tender and not frost hardy at all. I wonder if there's another sort that's listed under a different name? Help please somebody!

Well, there are about a half dozen species of Hibiscus cultivated in the USA. Most of those in my neck of the woods are the evergreen, subtropical H. rosa-sinensis. It would be an indoor-outdoor shrub in the UK, since it can't take much frost at all. H. syriacus is a hardy (to -26º C) deciduous shrub with similar flowers, except they range more into the blues than H. rosa-sinensis, and don't have any convincing yellows or oranges. Another one occasionally seen is H. moscheutos, which is an even hardier (-28º C) shrub-sized, herbaceous perennial with huge (30 cm wide) white, pink, and/or crimson blossoms. Most other species aren't very common in the garden.
I'll admit that I was assuming that the one in question was an H. syriacus, but H. rosa-sinensis has similar sensitivities concerning bud drop.

I've just dug out the label from mine and it's Hibiscus syriacus White Chiffon "Notwoodtwo". The label doesn't mention frost-hardiness but as I said, it's a very common plant around here - every one of my neighbours has one or more out in the garden and we don't move them inside in the winter, nor are they protected in any way. I have seen blues, reds, yellows and all shades in between, including my lovely white one......

Thank you Tug and Cestina - Had another look at the RHS book and sure enough there it was,syriacus, hiding and easily missed. Another thing for the wish list!