I would not doubt that parts of elderberries have some poisonous qualities, depending upon the amount consumed. The flowers of this species are eaten by people, so I wouldn't worry about flowers too much.

If your dogs are in the habit of chewing on or digging up plants other than grass, you might cage the young bushes for a while to protect the bushes. You could watch to see if your dogs seemed particularly interested in them.

I believe that symptoms of eating raw elderberries of some other species include nausea and vomiting. Dogs are good at vomiting, so I doubt that they would be in much danger from poisoning even if they ate quite a bit of the plant. If you had a pet rat, you might worry more, since they can't vomit.

I would worry more about slivers of wood getting into the wrong places if your dogs eat (and swallow) woody plants.

The green berries are toxic to humans. The fully ripe berries are much less toxic (you can eat a few raw without doing much harm, but it's not recommended), and they lose their toxicity when cooked. Roots are toxic, and may inhibit other plants grown nearby. The stems and leaves should not be used medicinally except under expert supervision. Most plants of the elder family are poisonous - the one usually recommended for culinary and medicinal purposes is Sambuccus nigra, the Black Elder. The American elder, S. canadensis, can be used in similar ways. I'd be extremely careful with any other species.

yes make sure you cook the elderberries before eating them. they will not kill you but will make you a bit not feel well. I think they will give you a nasty headache.

elderberries are usually cooked anyway making jams and pies. just not to eat a lot raw cold before cooking. the elderberry contains a chemical that is big and long. when heated the long chemical breaks into two shorter ones and then is safe to eat.

When I was a kid we would go in the fields and eat the berries and make elderberry juice from the flower heads.
Never had any problems being sick. Of course it might be like tomatos where some people might be more sensitive to the plant.

i don't know if it is all the elderberries or just certain varieties but the leaves contain certain compounds that turn into cyanide. We eat the wild elderberry here in south Texas and have never had any problems. For a fact i do know there is a particular variety of elderberry that is indeed very poisonous. For the life of me i can't remember the name just now.
My MIL makes Elderberry jelly and cobbler we also have a winery in Sour Lake that makes elderberry wine.