Dahlia 'Bishop of LLandaff'

I read some where that by pinching the first bud off promotes more growth in more buds. as for planting them outside now is fine I planted some of mine out before we had the snow at the begining of April. It looks like they have all pulled through. Some are behind the others in height, some are already flowering, but they are all growing.

I've heard Bishop of Llandaf is hardy and can be left in the ground all the winter.I haven't tried it with mine but I grow it in a pot and put it in shelter for the winter.
Sorry I haven't answered your question about the buds, but just something else about this Dahlia.

Our Bishop of LLandaff has come through winter well, you have done no harm and to keep flowering well Dahlias nedd constant dead heading.

New shoots on dahlias are caviar to slugs - I dare not leave mine in the soil over winter as they get eaten to death in spring