The following outdoor plants can be deadly to your pug if it eats the leaves or flowers:
~ Click the pictures to see a larger version ~
Azalea
Castor Bean
Crocus
English Holly (especially the berries)
Foxglove
Jimson Weed
Mistletoe
Oleander
Poinsettia leaves
Sago Palm
Water Hemlock
There is also a Cocoa Mulch that has been found to be toxic to dogs, so please avoid using that in the flower beds that your pugs can get to.