Arboretum Wespelaar grows a number of trees and shrubs from the temperate regions of the world. The Arboretum is well known for its extensive collections of Acer, Magnoliaand Rhododendron as well as some less familiar genera such as Clethra, Franklinia, Lindera, Malus, Stewartia etc.. These collections have been planted throughout the 20 hectare of the Arboretum.

The collection was started in 1985 by Philippe de Spoelberch, a passionate dendrologist, and is today owned and managed by the Foundation Arboretum Wespelaar. It has become a world class Arboretum and scientific institution.

Botanical explorations around the world resulted in the introduction of many plants from known wild provenance. Of the 2023 different taxa (species and varieties) represented in the collections, 177 appear on the Red List of threatened plants.