Perhaps Abutilon theophrasti, velvetleaf? Here is a link that might be useful: Link to info

You could try a number of penstemon species such as penstemon eatonii, penstemon barbatus coccineus, or penstemon pinifolious. All of which are great drought tolerant/heat resistant hummer plants. Although in Phoenix i would give them part shade since it gets so hot. Another possibility could be red-hot poker which is relatively drought tolereant as well. Im sure aloe sp. would also thrive in Phoenix, i had a huge aloe plant in my front yard when i lived in california(Zone 9 as well) and it drew in the hummingbirds when it was in bloom.

Peperomia glabella Looks like yours might have in addition been one of the forms sold as "red stem" or "red stemmed".

LOTS of plants are toxic to dogs. Probably more that are than those that are not. Most dogs are too smart to graze on poisonous plants in the garden but keep them supervised if you have concerns. And you can thank the birds for your plant :-)