|Do you have any suggestions to keep dogs from digging up flower garden?|
|Many dogs love to dig, sometimes just for fun, sometimes to excavate a place to curl up in the cool soil.
Have you considered one of those "invisible fences?" You could then decide what parts of your yard you want dog-accessible, and what you want to protect. It does require some work to train the dog, but it's do-able. That's the route I'd take if I were you.
Otherwise, you can do things like lay down chickenwire over the beds to make digging difficult (this works for cats, anyway), or install fencing. If you are willing to take some time to train the dogs -- and they are willing to obey! -- you could install some low, temporary fencing to put around her garden, and train the dog to respect the contained areas as off limits. I think problems arise because dogs can't distinguish what's OK to dig and what's not OK to dig. (And they gotta dig!)