Collection Displays Trees at their Best

This article was first published on 03 Apr 2013.

At Dunedin Botanic Garden the arboretum covers just over 2 hectares.  But what exactly is an arboretum?

The best definition I have found is ‘a place where an extensive variety of woody plants are cultivated for scientific, educational and ornamental purposes’.  In general terms this is a collection of different trees.

What is great about arboretums is that you can view specimen trees in their full beauty, away from other plants. Arboretums ideally allow enough space for the woody plants to reach maturity.

Arboretums are relatively low maintenance but some management is required to achieve the best outcome for the trees. Formative pruning at a young age sets up the tree for a healthy future.

Weed suppression around the base of the tree can be done through herbicide sprays and/or mulches. It is often under estimated how much moisture grass can remove from the soil.  This effects the growth of larger trees. Last year at Dunedin Botanic Garden we used old coffee grinds as mulch which successfully smothered the grass and will help retain moisture in the soil.

Having a clear area around the base of a tree reduces the need to mow close to the tree and eliminates the possibility of mechanical damage to the trunk while cutting the grass. Eventually, when the trees get larger, they suppress the grass through shading and moisture uptake, reducing the amount of management.

The arboretum at Dunedin Botanic Garden is on the sunny slope between the rock garden and aviary.

Dylan Norfield is Geographic and Arboretum Collection Curator at Dunedin Botanic Garden.