When the land was purchased, the recorded timber on the site consisted largely of elm and willow. The first plantings in the University Parks were carried out under the direction of William Baxter, Superintendent of the Botanic Garden (and later of the Parks), and supervised by the Reverend T H Hopkins, Fellow of Magdalen College and a Curator of the Parks.
In December 1867, it is recorded that 28 trees were planted at intervals of 100ft with shrubs between to form a winter garden. This is thought to have been along the northern boundary of the Parks.
In the first annual report of the Curators of the University Parks in 1889, William Baxter produced a list of some 400 trees and shrubs located in the Parks.
Over the decades disease and the effect of storms and drought have taken their toll. In the 1930s the Curators were alarmed by the presence of Ceratocystis ulmi in the locality – Dutch elm disease was about to dramatically affect the landscape.
An extensive collection of elms, comprising more than 20 different varieties, were then flourishing in the Parks. Over the next 50 years almost all were to be felled, mostly in the 1970s. In the gaps which were created many fine semi-mature trees are now developing.
Photographs dating from the 1930s show the existence of flower borders, rose beds and a small ornamental goldfish pond near to the North Lodge Gate.
A handbook prepared in 1936 by Mr Harvey Dunkley indicated that many of the trees listed by Baxter in the 1880s had not survived. The introduction to this guide records the existence of over a thousand individual trees and gives notes on the more interesting or conspicuous specimens, numbering about 250 different varieties including a large number of elms, some of which were already infected with Dutch elm disease.
In 1953 the Curators published a second guide, on the centenary of the setting up of the Parks. This was superseded in 1977 by the last formal publication. Unfortunately, almost half of the trees listed in 1977 have been lost as a result of disease, drought or storm damage.
A group of trees was planted in 1953 to commemorate the Coronation of Queen Elizabeth II. Further trees were added here in 1977 to celebrate the Silver Jubilee, along with a circle of ten Aesculus hippocastanum (horse chestnut) north of the cricket field.
In 1989 a number of oaks were planted along Middle Walk to replace an avenue of elms. Smaller ornamental trees such as Malus (apples), Prunus (cherries) and Sorbus (rowans and whitebeams) were planted between the oaks in 1993. As these are quick to mature, they provide short term interest and colour in this area.
The plantings within the Parks have been greatly enhanced over the last 25 years. The diversity of the tree collection has significantly increased and the attractive and interesting collection of shrubs and herbaceous plants complement the collection held within the Botanic Gardens. This provides colour and interest for visitors all the year round. Large quantities of bulbs have been added to enhance the planting carried out in the 1930s.