AusBonsai

Can anyone tell me the variety of Cherry used as growing stock for weeping Cherries.
Cheers
Kirky

Usually the same as used for fruiting cherry. The 2 most common cherry root stocks are Mazzard F12-1 and Colt but Mahleb (prunus mahleb) is also used.
Mazzard is a very old selection of P. avium so it is a type of sweet cherry same as the ones we eat.
Colt is a hybrid developed specifically as a rootstock for other cherries - Prunus avium F 299/2 x Prunus pseudocerasus. It is also registered so users are supposed to pay a royalty to the company that developed that variety.
Mahleb is listed as suitable for deep, sandy soils and is not as long lived so probably not widely used.
Kentish and Morello sour cherries are sometimes used as a dwarfing rootstock so not as likely to be used for flowering cherry as the growers usually want a quick growing rootstock to get a standard trunk faster.

My guess is the rootstock is most likely to be Mazzard or P. avium.

Thanks Neil, I have a weeping Cherry that has started to send up suckers over the last three years and it has lovely single white flowers that grow in a cluster. So far I have three of four to bonsai. Very hardy and quick growing. You have narrowed it down to two for me its either Mazzard or prunus Prunus avium Stella / Colt. Many thanks
Cheers
Kirky