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 underestimated how much moisture grass can remove from the soil. This affects the growth of larger trees. Last year at Dunedin Botanic Garden we used old coffee grinds as mulch which successfully smothered the grass and helped 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 from the mower. Eventually, when the trees get larger, they suppress 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 the aviary.
- Dylan Norfield is geographic and arboretum collection curator at Dunedin Botanic Garden.
