There are many plants that can be kept with axolotl!
I will give you a list of cool water plants. You dont want tropicals because it is too cold for them and none of those terrestial plants that stores pass off as aquatic, we don't want any dead plants.
Here we go!
Valisneria spiralis
Eloda
Lysimachia Nummularia (creeping jenny)
Sagittaria platypylla
Potamogeton crispus
Eleocharis parvula
Ludwiga
Duckweed
Hornwort (good at combating algae, fast grower)
Various aquatic mosses, such as java moss
Saururus cernuus
Salvinia
Riccia Fluitans
Spatterdock
java fern
Plants NOT to buy that are often sold as aquatic:
anything that is a Dracaena, such as lucky bamboo, Caladium, Mondo grass, fountain plant
this is not a complete list, but a nice sampling of plants to keep with Mr. Axolotl!Remeber, plants need about 10-12 hours of light so make sure you have a light above your tank for healthy plants.