No expert, though I've grown several varieties, but they never bloomed more than one season, probably because of neglect. I grew mine in pots.

Here's some info from Floridata.com:

https://floridata.com/plant/1006

And some more info from UF's EDIS/ IFAS:

http://edis.ifas.ufl.edu/fp169

Hope this helps...

Dahlia tubers often have multiple growth points or 'eyes' and each will produce a shoot/stem. Feel free to leave as many to develop as the plant produces :-)

I just leave mine. Whatever sprouts, sprouts.

Thanks, I'll leave them alone then.

Forgot to mention the ones I've grown did that as well, and I pruned nothing.