crescere is also "to grow" but reading the usage in Reverso.com, the difference seems to be crescere is used mainly when talking about the actual act of something growing: it is used for when children grow and grow up, beards grow, grass grows, toenails grow; it is also used for raising children.

coltivare is "to grow" or "to cultivate" - it refers to the purposeful planting and tending of something to produce either a crop or some benefit, like cultivating friends, cultivating attitudes, etc. I hope that helps.

An apple tree is un melo. Sort of cute.