They certainly work the wild 'dog' roses here in the UK - these have single
flowers - and solitary bees also work them.
We are less likely to see bees on the cultivated roses, probably because
they cannot get to the centre of the flower until it has opened fully (by
which time many gardeners will have removed it).
Best wishes
Peter Edwards
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www.stratford-upon-avon.freeserve.co.uk/
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