MY LIFE WITH PLANTS: UC Santa Cruz Arboretum

By Jim Bishop for Let's Talk Plants! September 2021.


This past April, I was fortunate to do a long-awaited return visit to the UC Santa Cruz arboretum. I had previously visited in 2012 in route to a San Diego Horticultural Society tour of San Francisco Bay Gardens. It has the best collection of Australian plants outside of Australia and I was anxious to revisit it after a trip to Western Australia back in 2016. It also has outstanding collection of South African plans. The garden is a bit more of a plant collection than a designed garden, but that is just fine with this plant nerd.


Here is how UCSC describes 135-acre arboretum on their website:


“The UC Santa Cruz Arboretum & Botanic Garden’s rich and diverse collection contains representatives of more than 300 plant families of Mediterranean climates. The garden maintains collections of rare and threatened plants of unusual scientific interest. Particular specialties are world conifers, primitive angiosperms, and bulb-forming plant families. Large assemblages of plants from Australia, New Zealand, South Africa, and California natives are displayed on the grounds. Many of the species in these collections are not otherwise available for study in American botanical gardens and arboreta.”

Leucospermum tottum X formosum 'Spider' - Spider Pincushion


The history of the garden dates back to the founding in 1964 with the gift of 90 varieties of Eucalyptus. While the plantings have a particular focus on Mediterranean plants from the southern hemisphere – Western Australia, South Africa and Chile.

South African Erica

The large diversity of natural occurring rock types includes granite, schist, limestone, and several types of sandstone creating countless plants zones coupled with a variety of terrains creating many microclimates. The Arboretum was one of the first places outside of South Africa to successful grow Proteas from seed. They also have tested hundreds of Australian plants releasing the best and easiest to grow to nurseries and gardeners via their Koala Blooms program.

Eastern Australia Telopea

I allowed myself several hours to explore as much of the garden as possible. One of things I noted was just how large some of the plants have become. I’ve noticed this myself about Australian and South African plants. In the right conditions many continue getting larger and larger each year totally beyond the mature size listed on a plant tag. However, most of my oversized plants are mostly less than 10 years old while some of them at the Arboretum are approaching 50 and have never stopped growing. It made me rethink some of my recent plantings wondering that maybe I’ve planted things too closely.

Australian Banksia

So, if you are looking for some inspiration and unusual plants, I strongly recommend a visit to the UC Santa Cruz Arboretum.

Leucospermum 'Brandi Dela Cruz'

Past President, Jim Bishop, is the current publicity chairperson on the Board of the San Diego Horticultural Society and he was the 2019 - 2020 SDHS Horticulturist of the Year among many, many other things.