The “prehistoric garden”, with a ginkgo (Ginkgo biloba) in full autumn glory on the left, and monkey puzzles (Araucaria araucana) with their characteristic silhouette on the right. — The “prehistoric garden”, with a ginkgo (*Ginkgo biloba*) in full autumn glory on the left, and monkey puzzles (*Araucaria araucana*) with their characteristic silhouette on the right.

To paraphrase the US Post Office’s slogan, neither snow nor rain nor heat nor gloom of night stays the three tree geeks from their appointed rounds…

We survived a day of blistering heat in Mission Bay last summer, and a marginally cooler day in Westwood Park in early November, but Sunday, December 13, was our first encounter with real rain. And what a day it was, with more than half an inch adding to the half inch received Friday night, to roughly triple San Francisco’s seasonal rainfall to date. If you’re keeping track, that’s several inches below the average at this point in a rainy season that begins in October and runs (if we’re lucky) for almost six months.

Interpretive panel in the park, showing San Francisco’s rainfall patterns compared to other American cities

To our surprise, we were not the only folks strolling around Salesforce Park. Pathways are well-paved, and occasional shelter provides protection from the heaviest downpours. An interpretive panel at the western end of the park, attached to the railing between the two succulent gardens, explains the natural rainfall pattern experienced in San Francisco. Most of California enjoys a mediterranean-type climate, with rain falling during the cooler months and a nearly complete lack of rainfall during the warmer months. The panel provides an illuminating graphic comparison of the rainfall patterns in other major US cities; it’s clear that San Francisco is pretty unusual in its winter-only rainfall.

Mike, our fearless leader, had already created a walking tour of the park’s trees, which you can reach by clicking here, so we merely enjoyed a three-hour stroll-and-chat about the gardens. The glorious array of trees, shrubs, herbaceous, and succulent plants in the middle and around the perimeter of the three-block-long elevated park make up the greatest diversity of plants in any public space in the city, outside of the San Francisco Botanical Garden. Arranged by geographic origin, or in other distinct categories (succulents, palms, oaks), the plants offer a tour of the world’s flora, with an emphasis on the mediterranean-climate regions of southern Europe, North Africa and the Near East, California, central Chile, southwestern South Africa, and portions of South and Western Australia.

One of two “desert gardens” in the park; the plants with the orangish trunk at the back and upper left are dragon trees (Dracaena draco) from the Canary Islands, Madeira, Morocco and Cape Verde — One of two “desert gardens” in the park; the plants with the orangish trunk at the back and upper left are dragon trees (*Dracaena draco*) from the Canary Islands, Madeira, Morocco and Cape Verde

It’s unlikely that we’ll be dealing with snow around here, and nighttime usually brings a halt to tree touring, but if you find yourself anxious to get out on a rainy day this winter, we strongly urge you to make the trip to Salesforce Park and enjoy this bold, horticulturally rich garden in the sky. You’ll want to visit in every season; arborescent aloes are in flower now, along with some South African and Australian members of the Protea family. Later in winter, California natives will pop, along with those from Chile and the Mediterranean.

We can also recommend some take-out from Luke’s Lobsters, an urban shack at the corner of 2nd and Mission streets. The lobster rolls are the best this side of Maine, which, incidentally, does not enjoy a mild mediterranean climate like ours.