Photos below of two 34 month old Sabal Louisianas potted in the same soil mix in a three gallon container, watered/fertilized the same, and placed next to each other as they grew. On the left, a fine specimen from an ancient twenty foot trunking Sabal Louisiana. On the right, a soaring(already 38 inches tall!)specimen from Amazinggardens seed source.
Here is the parent of the above left Sabal, photo courtesy Bryan Swinney.