Lily Miller Brands Rose and Plant Food, according to the research and material safety data, has no ecological concern and is considered a non-hazardous plant material. This means it's safe for routine contact by animals and other plants as well as non toxic to water tables.
Ingestion by dogs (relatively common believe it or not) may cause GI tract irritation in certain amounts and it's suggested that this be treated symptomatically.
The material safety report can be viewed here Click
What has me most concerned is that he's still showing this degree of discomfort and panting. Now, it's possible that with all the excitement and attention he's become a bit nervous, plus the vomiting and diarrhea are going to be stressful by itself, so this will be a judgement call on your part. No one knows your dog like you do and you must trust your instincts with him.
If you feel comfortable doing so, the symptomatic treatment for this is multi stepped:
1. Withdraw food and water until the dog has gone six hours without an episode.
(If vomiting continues more than 24 hours, lethargy or fever develops, seek medical attention without further delay)
2. Introduce just one or two tablespoons of water every 15 minutes or so. If the dog can keep it down after a couple hours, try increasing the amount of water. When you're sure the dog is maintaining, try offering some plain chicken broth or even Jell-O.
Once the dog goes 12 hours without vomiting you can begin introducing bland foods; however, if the vomiting begins again, go back to #1.
3. Bland diet introduction will include boiled chicken and rice (no skin and skim off all fat). About ½ cup of meat with 1 ½ cups rice and some of the broth. You can also use boiled or baked potato instead of rice.
- only offer a couple tablespoons of this mixture/soup at a time -
Remember, if the vomiting begins again, it's back to #1.
4. The next day, increase the amount of single feedings and gradually add some of the dog's regular food. You should still spread the feedings out into four or five meals throughout the day rather than the typical one or two.
You have to make sure the dog maintains on this for 24 hours. A couple spoons of food every hour or two.
If the vomiting re-starts, it's time to make the vet appointment.
Now, all this said, I reiterate that you need to trust your own instincts on this. You can see him and you know what you feel.
There is never anything wrong with seeking medical care. If your own vet isn't open, often the answering machine will have 'after hours' vets to call for emergencies.
Emergency care facilities are often regular vet offices that have 'after hours'.
Your companion may have ingested a parasite inhabiting the soil and it could very well be doing this and thus your description of "Montezuma's revenge" diarrhea.
As long as he's going to be keeping you up with his discomfort - I'd like to see you get him seen just for peace of mind.
Please let me know how you all make out.