About Us

Our philosophy is to use proven best practice to produce high quality trees at a reasonable price that are hardy to Canterbury conditions.


The Gorge Nursery was established in 2007 and is owned and operated by Sis Johnston. It is 1.5ha with approximately 7000 ornamental trees. It is located at Ashley Gorge near Oxford. Sis completed her Amenity Horticulture Apprenticeships with the then Waimari District Council. Sis has 18 years’ experience in the nursery industry, giving her a good skill base to pull from.

The Gorge Nursery specializes in growing two main grades of containerised ornamental trees, a 25lt and a 45lt grade with a mix of deciduous and evergreen exotic and also native trees. These trees are grown to survive in harsh Canterbury conditions, be it out in an open paddock or exposed situation or in a sheltered garden.

Growing an A grade tree begins with sourcing good quality stock, using a good quality potting mix and employing good nursery practices.

As explained further down below we use tried and proven nursery practices; growing trees in open surroundings without the use of canes, and using pruning techniques that result in the tree being stronger and having more uniform shape. These practices result in strong hardy trees with good shape.

We are passionate about trees and like to give one on one time with our customers to help select the right trees to fulfil their vision, which will do well in their location.

Growing in the Ashley Gorge

Growing trees at Ashley Gorge is often a challenging time. We experience strong winds from the North- west, and the occasional good dumping of snow. We cope with transpiration by watering up to 3 times a day to help reduce hydrophobic soil mix conditions occurring – the less energy the tree has to use sucking up water the more growth it will put on. If a tree wilts, the wilting will reduce the growth rate for several days.

The spin off from the wind of course is that our trees leave the nursery hardened off to the wind which gives them a far higher survival rate than trees that have been grown in a sheltered environment.

We have a slightly slower start to spring than down country but have a longer growing season in the autumn largely due to the climatic influence from the Gorge Wind.

“Our philosophy is to use proven best practice to produce high quality trees at a reasonable price that are hardy to Canterbury conditions.”

The Way We Grow Trees

This is determined by understanding the way trees grow i.e. the physiology and morphology of the tree. Physiology being the way in which organisms or parts of organisms function and morphology is the study of the external form of organisms.

We start with either producing or buying in, high quality GOL’s. (Growing on lines) The GOL is root pruned (to remove damaged or over-crossing roots and to improve root structure) and form pruned at bagging up time. They are planted into a high quality potting mix.

We understand the importance of growing a tree with a self-supporting stem – this happens right from the earliest contact we have with the tree. We achieve this by:

  1. Not employing the practice of caning trees which in turn allows the secondary thickening tissue to develop, and,
  2. We leave the lower branches on the tree for the better part of the growing season as these lower branches aid the thickening of the stem. The only time we use canes is when we ‘cane to train’. Some species love going every which way but up, so we put a cane on them for the first part of the growing season to get a straight trunk and then remove it in the second half of the season to strengthen and harden.
In our nursery we practice ‘Natural Target Pruning’. During the growing season all the trees in the nursery are examined and form pruned if necessary. Form pruning is when double leaders and dominant branches are removed. At the early stages of a trees growth some branches will exhibit dominant form. These branches are removed to push the growth into the top leader and to allow small forming branches to grow into that space which creates and even branched tree. In most cases you are restoring symmetry to the tree.

Every time a tree is bagged on the root ball is given close attention. Any circling roots are removed and all root balls are teased side and bottom which helps form a radial root system. Trees are tied onto a line which stops them from blowing over but still allows them to move in the wind.

The best trees are selected in the early autumn for bagging on, thus we are only growing on the best trees into larger grade trees.

In summary, our growing techniques produce a tree with the following qualities:

Above Ground

  • Health and vigour
  • Pest and Disease Free
  • Injury free
  • Self-Supporting trunk
  • Tapered trunk
  • Apical Dominance
  • Crown symmetry
  • No Included bark
  • Trunk position in Bag – central
  • Graft unions – sound

Below Ground

  • Free of damage and decay
  • Root Direction – down and outwards
  • Root ball occupancy
  • Height of root collar at the correct level in the bag.