Alan Gould wrote:
[...]
That's the Myrobalam plum - Prunus cerasifera. The fruits grow like
cherries but taste like plums. We have lots of them in our hedges
and
they produce masses of fruits in all the colours of cherries. They
are
very early flowering, some of ours are almost in blossom now. In
years
of late frosts, that can mean loss of harvest.
[...]

Ah, right: somebody to ask. Is this _P. cerasifera_, called
"Cherry-Plum" in the Collins _Field Guide_, the same as a bullace? Or
is a bullace the fruit of the "wild plum", _P. domestica_? The Guide
rather irritatingly doesn't mention bullaces, though it's a common
enough word, and OED1 uses the obsolete name _P. insititia_ (though
it does call the plant "semi-cultivated", which is interesting: I
assume it means planted deliberately, or encouraged, in hedgerows but
not in orchards).

Mike.