Answer: Below is a web page of a listing of poisonous plants, from Cornell University. This should help you decide what plants to avoid.
Below is a web page for a list of edible flowers. I'm not aware of the foliage of any of these plants being poisonous, but I'm not absolutely sure.
Consider a combination of these edible flowers, plus some ornamental vegetables such as multicolored 'Bright Lights' Swiss chard and scarlet runner beans. You can mix is some of your favorite garden vegetables, for an attractive, safe, and productive garden.
You might find the following book helpful:
"Accessible Gardening for People With Physical Disabilities : A Guide to Methods, Tools, & Plants" by Janeen R. Adil
Also, you might enjoy these articles from NGA's "Growing Ideas" newsletter:
I hope this is helpful.
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