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JUNE MEETING REPORT: Summer Dry – A Very Succinct Description Of Our Weather w/Saxon Holt

By Lynn Langley.

Saxon Holt.

Saxon Holt, author of “Gardening for Summer Dry Climates,” presented an eye-opening, yet practical, paradigm shift in our approach to gardening. His mantra consists of a very simple statement, “Garden where you are.” Of course, gardening where you are means that the characteristics of a particular microclimate are understood. To help with that, Saxon introduced the World Map of Koppen Climate classification that separates the world into 31 classifications of vegetation-based biomes, giving each region a three letter designation. On the Koppen map, designations for a Mediterranean climate are C meaning mild temperature, s meaning dry summer and then three choices for temperature – a. hot summer, b. warm summer and c. cool summer. San Diego’s Koppen class designation is Csb or mild temperature, dry and warm summer. These designations help define the ecotope, the smallest ecologically distinct landscape featured in a landscape and classification system. Ecotones are border zones where ecological systems meet and mingle, sometimes forming new communities. By using the smallest, geographically specific niche gardens as building blocks, gardeners help to create climate tolerant green infrastructure that connects gardens to the ecosystem and ecotones. Gardens and gardeners can help restore the lost balance in nature.

Saxon Holt has further divided the West Coast into 4 sections: Northwest, Northern California, Interior Valleys and Southern California. The Northwest is characterized by Oregon Oaks, Northern California by oak woodlands and rolling hills, Interior Valleys by native oaks and plants that can handle high heat and a high evapotranspiration rate, and Southern California by coastal scrub and Torrey Pines. Each of these zones have their own iconic look with climate-adapted native plants. For him, a gardener’s focus needs to change from drought tolerant to climate tolerant plants. For growing native plants in San Diego it is important to remember to not only collect water in the winter but to use that water in the winter to encourage robust root development that will help the plants withstand the dry summer. Other adaptations that can be considered to help with the summer dry climate are: a grey water system to reuse some of the house wastewater, installing cisterns or other water capturing systems, the use of bio-swales in the garden, and continuing to focus on climate tolerant trees and shrubs. But there are changes on the horizon. The Mediterranean climate that has been a hallmark of this area for so long may be evolving because of global warming. Monsoonal systems bringing summer moisture and lightning have become more frequent. The question is will they increase in frequency and regularity, making the area no long summer dry? Only time will tell. And once again, Saxon Holt emphasizes that the ultimate inspiration for all gardeners is to “garden where we are.”

His website, The Summer Dry Project, outlines in great detail his beliefs about the summer dry climate and the need to shift gardeners’ focus to selecting climate tolerant rather than drought tolerant plants. His mission statement puts it succinctly. “And now, in the midst of tumultuous climate change we realize its all the more important that gardeners be stewards of the land, attuned to the local environment on behalf of all creatures. Every act we do adds resiliency.” For Saxon, our gardens are part of the solution to combating climate change.


The San Diego Horticultural Society is honored that Saxon Holt of the Summer-Dry Project, and the book Gardening in Summer-dry Climates . . .

. . . allowed the SDHS to feature the recording of his great Zoom presentation to the SDHS general meeting on June 14, 2021, all about Gardening in Summer-Dry Climates, on our YouTube channel for a limited time run of six weeks. Those six weeks have transpired and the recording has now been taken down per our speaker's agreement.

It has been replaced with a message from SDHS president Karen England that you can view here;


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