If you have children or pets, you should be particularly aware of which flowers and plants are poisonous when ingested. This Old House compiled a list of twelve plants which are fairly common, but potentially dangerous if eaten. Here's a sampling:
"Swallow any part of this plant, and you're going to look as bad as you feel. While drooling from the mouth and teary-eyed, you'll begin vomiting violently, just as your pulse slows down and low blood pressure sets in. Death can occur shortly after falling into a coma or during a violent seizure.
"Swallowing hydrangea is like popping a cyanide pill. The present poison, hydragin, is a cyanogenic glycoside, meaning it will cause shortness of breath, dizziness, fainting, and a rapid pulse, along with a drop in blood pressure that can cause convulsions and death."
"Think twice about growing one of these babies in your yard, especially if you have little ones: a single leaf contains enough toxins to be lethal to an infant or small child. Like other poisonous plans, ingesting it first affects the digestive system with vomiting and diarrhea, then poisoning progresses into life-threatening circulatory problems. If your heart's still ticking after that trauma, oleander can also deal a fatal blow to your central nervous system, causing seizures, tremors, and coma that can lead to death."
• Read More: 12 Deadliest Garden Plants/This Old House