Plant a tree for a long lasting memory of a loved one.
Here are a few symbolism of trees that may help with your choosing as well as a few named trees and shrubs. Also trees feel look nice at different points of the years.
You could also consider there...
You could also consider there birthday tree which can be found here.
Oak: Strength and knowledge.
Dogwood: Kindness, stability and determination.
Silver Birch: Lady of the wood.
Rowan: Protection and inspiration.
Hazel: Wisdom and learning.
Yew: Tree of rememberance