Plants take some time to get used to tank conditions. They'll look poorly for a while and then once the animals, water and plants get used to the conditions, you'll notice some growth.
Make sure the water, light and food (nutrients) are right. Large, weekly water changes are needed. Check the lighting for your plants. The watts per gallon using T8s needs to be between 1.5 and 2. Make sure you provide the right nutrients. I like liquids, because they're easy to dose. FloraPride from Tetra is a good one. Just dose a little a couple of times a week.
Follow the steps above and give the tank some time.
"Fear not my child, just change the tank water."