The "big spikes growing on the side of the tree" may be from below the graft. If they have upright, non-weeping growth different from the original weeping cherry, that is certainly the case.

These will very likely be of Wild Cherry (Prunus avium), which does bear fruit, though the cherries may be rather sour (though quite a lot of Wild Cherries do have very nice fruit, too). The flowers of Wild Cherry are single and white, not pink or double like the original, but still very attractive.

Resin

thank you "pineresin" I have heared on the radio of a product called Enviro Tree, it will fertilize trees and hepl tree growth. I wonder whether it will help our sadly looking weeping cherry tree. all main branches are dead, exept there are finge size spikes on the side of the tree. We woud like to save the tree if possible. Regards Dieter

Can you post a photo of the tree?

I doubt that fertiliser will help much.

Resin

I have posted some pic's on yahoo, please go to:
http://new.photos.yahoo.com/dschonemann/albums
in the mean time i have removed all dead branches, exept the center main branch for supprort.

Here is a link that might be useful: cherry tree

Thanks! though you'll have to tag the photos as available for public viewing (they aren't at the moment)

Resin