For dogs and cats, not so much. Symptoms include: vomiting, diarrhea, and tremors. It mostly causes dehydration, due to severe vomiting and diarrhea. Gardenia – Unfortunately, the white and fragrant blooms of this shrub can take a toll on your pet’s health.Click to see full answer. Similarly, you may ask, are gardenias toxic to pets?Gardenia. Clinical Signs: Mild vomiting and/or diarrhea, hives.One may also ask, what flowers are not toxic to dogs? There are some plants and flowers listed below that are non-toxic to dogs but can have seriously adverse reactions to cats. Toxic Plants aloe vera. autumn crocus* azalea* baby’s breath. begonia. chrysanthemum. daffodil. elephant’s ear. Consequently, is Gardenia Oil poisonous to dogs? Rena Sherwood. Gardenias can be poisonous to pets depending on how much the pet eats and how small the pet is. Generally, the smaller the pet, the faster they can become sickened by a gardenia. If the gardenia has been treated with pesticides, it will be even more toxic.What plants are poisonous to dogs? There are many house and garden plants that are poisonous to dogs, here are some of the most common ones: Aconitum. Amaryllis bulbs. Asparagus fern. Azalea. Cyclamen. Daffodil bulbs. Day lilies. Delphiniums.