"David Hill" wrote in message ...


Not every tuber will produce a new plant, it depends on the eyes that form
at the top of the tuber where it joins the stem.
I was going to say if you had several of each variety lift some of each and
leave the others in the ground, covered as you described.
It's mostly the wet that kills off the tubers, though they wont take the
tubers getting frosted.
As for lofting and dividing, there are a lot of clips on google that show
you what to do, mostly with first year tubers, this American one shows a
clump that is a little larger, and despite her American pronunciation of
Dahlia it is quite good.
http://www.finegardening.com/how-to/...g-dahlias.aspx
The Americans split their dahlias down to "Chicken Legs" that is single
tubers with one or two eyes, in the UK we tend to grow from cuttings or
from clumps of a few tubers.
if you have more questions I will try to answer them.

Just a quickie David. My oldest plant which has some sentimental value is
'New Baby'. For the last 2 years, it's showing signs of tiredness. This year
the buds haven't yet opened and it's half the height of its neighbours.

Is it too late at 9 years old to revitalise using the above division method?
Perhaps I should have done this at year 4.