I have 2 red palm trees for 6 years already, they don’t seem to grow well but the small trees beside them grow a lot. Can someone advice how to care and grow them into final state of 4-6 tall red palms each?

1. What’s the right way to cut/prune to the final state?
2. Do I need to prune the small trees (suckers?) beside them?
3. Is putting small white stones around the tree harmful to the tree’s growth?

1. Did you have to cut off some offsprings/bushes around the palm?
2. Do I put fertilizer at the center/middle of the tree's root area, or around the pebble stones area (will remove the pebble stones)