I have two pygmy date palms that were planted after building a pool 3 years ago. They are located on either side and behind a small rock waterfall. They are growing so fast, they are taking over the waterfall area. There are other palms and tropical plants behind them which you can barely see. It looks very unkept. I know how to prun the other plants but not the pygmy dates. Any insight and suggestions would be great.

Thank you