Root pressure can push water upwards by not more than few meters
this pressure is enough to supply water from roots to leaves in small herbaceous plants
however there are trees as tall  as 80-120 meters like red wood and eucalyptus. in such plants water has to pushed several meters upwards against gravitational pull
both transpiration and root pressure help to pull water upwards by several meters in tall trees and helps to supply of water in tall trees
this kind of wonderful and natural mechanism can be seen only in plants