Generally speaking, without closeup picture of the leaves, buds, bark and flowers, we can still most likely presume this is some kind of plum or cherry trees. These belong to the Rosaceae family of which there are 4,828 species in 91 genera, including apples.

So, if those trees are the source of the problem, you'll have quite a time protecting him/her from this type of allergen because these are ubiquitous.

(There is a 'Name that Plant Forum' on these boards).

Have you seen the pup eating or chewing on plant materiel or anything else that might upset his stomach? Many kinds of plants can have a mildly to modest toxicity if taken internally and if they eat grass, they can vomit from that.

It might be best to keep the pup out of the yard during pollination time, but sorry, I am not a veterinarian and have no idea if pollens from these trees can cause any of the symptoms you describe.

Unfortunately since you only have a suspicion... you are going to have to watch your dog. As in every second they are out in the yard. Watch what they are sniffing into, chewing, digging. And watch for reactions. I would like to say it would be easier if pets can talk to us, but often enough humans have to go through a watch every second of it to figure out our allergies too.

This was recently circulated on our Nextdoor. Apparently Cocoa mulch is toxic to dogs. Don't know if you put any of this down.

https://www.greyhoundfriendsnj.org/info/display?PageID=8701

Iris, lilies and larkspur are also poisonous for dogs along with a bunch of other plants.

https://www.trustedhousesitters.com/blog/pets/pretty-yet-poisonous-plants-for-dogs-to-avoid/

My guess is Callery pear. They're not toxic to dogs.

My dog eats bunny berries but apparently can't eat a grape. Go figure.

I am as worried about physical damage from a dead rabbit's bones or mulch or if she tries to eat a whole hedgeapple than I am about a reaction.

Hi all- so sorry for the delay in response!

thanks so much for the advice everyone!!!! I did end up taking her to the vet and cutting off all low branches that she tries to get off the tree or just chews. Funny until someone doesn’t feel well 😬 But she’s been doing much much better since. And I’ve been sitting outside whenever they are out there to make sure she’s not sneaking them. Ohhhh puppies. Beesneeds, there were a few sticks that I hadn’t seen yet that she got into. She’s ok now :) Also the petals are almost gone so that’s nice!!

Thanks everyone! Really appreciate the help!!!!!! :)

Eek yeah I heard grapes are realllly bad. A long time ago my old dog ate Raisin Bran when a dog sitter was watching her and luckily she knew to rush her to the vet. So many things to pay attention to but they’re worth it! 💜💜💜