David in Normandy wrote:
I'm not sure if pith is the correct word. They are a cultivated variety
of blackberry around three times the size of wild blackberries but they
have a firm pulpy bit on the inside. The blackberry plant cost ?8 five
years ago from the local garden centre and this year it is running
rampant and is covered in blackberries. It is also thorn free which is a
bonus when picking them.


Ah yes, that bit. I've never quite understood how one is meant to
treat blackberries. They've never been a great favourite of mine.
They're like raspberry wannabies.

(they also take over the allotment entirely - not a single bit of
patch that doesn't have blackberry interlopers, and it's all thorn
and no fruit! Including, I hasten to add, right the way through the
shed and out the roof and window!)
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