What are ur lighting conditions, tank size, and what types of fish do u have...? Java is very hardy, I'd also consider anubias (they're very forgiving too).... Amazons would be ok, but are less hardy, they do well in loose substrate with an iron rich additive... You could try either (or both) liquid fertz or tabs....another choice is adding a planting substrate (slowly) that looks similar to ur gravel (most come in natural or black)... These can be pricey though...
If u want (depending on ur tank size) co2 is also an option...a few choices include dyi, small already made kits found at most lfs, or pressurized co2 (expensive, but very effective)...
I never really had success till I used a plant substrate and co2... Now however, I have to constantly prune and trim.... I know others have great success with gravel and sand, but usually they're a great deal more sophisticated then myself when it comes to lighting, ph, etc .....hope this helps...best wishes.... -mike