Every fish is different. It may be that you just need to experiment with plants to find species that will work for you. I have a gold severum that will destroy even tough plants, so I went with just rocks and
driftwood for that tank. I also have a planted 120 gallon with a Rotkeil severum pair, and that's been trial and error but overall is working out. The plants I've found that are a pretty safe bet are anubias, java fern, and cryptocorynes (I have several crypt species). There is also a lily plant in there that does fine. You'll probably have issues with most stem plants (I'm guessing based on your description that you have some type of hygrophila). Try a few of the plants I mentioned before you give up your severum... you may be surprised.
