I find that the tortoises will feed on what they need and will not overindulge in any one variety (berry or otherwise). Further, they will not eat plants that are bad for them. I have seen them "taste" with a partial bite, on a plant they had not seen before, then decide not to eat it ever again.
I have customers with morning glory and/or oleander in their yards and no dead tortoises. The torts simply know not to eat it. 
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AMAZON REPTILE CENTER


