I'm not sure who labeled hibiscus as "unsafe for consumption". It's definitely a safe plant for tortoises and dried hibiscus flowers are commonly used for making tea. So, you can continue to feed it, just "as a part of varied diet"oh okaythank you that makes sense. i suppose it is "hibiscus season" (i've never seen that many before!) so if she ate it for a month straight in captivity, she would done it anyway if she had access to the plant. i should stop though, because the plant said "not for human/animal consumption".
however, what about all the other plants in my yard? those could also have pesticides from a longtime ago (i'm not sure how long they last) despite them being here for years. i have a begonia that i give her every now and then, along with geraniums.
I think if you see snails, aphids, caterpillars and other little critters chewing a plant then pesticides have been washed out and it's safe to feed. I would not expect pesticides to reside in soil for more than 3-5 years but I'm not an expert in agroculture.