Green Roofs in San Francisco

In a spring escape, I was in San Francisco in late March. We visited museums, parks, and restaurants.

Roof, California Academy of Sciences

I had not been to the California Academy of Sciences in more than 20 years. In that period, the building was completely rebuilt, with a green roof. I had been doubtful about green roofs--where people grow plants on the roof. I know they have been used for millennia in parts of Europe, but those are wetter climates than San Francisco. So I wondered about watering and keeping plants alive in shallow soils. Or, if the soils aren't shallow, the weight on the roof. 

Big, Medicinal, and Long-lived, Veratrum californicum, False Hellebore, Corn Lily

California false hellebore, Veratrum californicum, is a big plant you can't miss. It is very toxic. Rising temperatures threaten it. Altogether a fascinating native American wildflower.

 California false hellebore, Veratrum californicum,
in the Colorado Rockies

Travel Story--Japanese Tea Garden in Golden Gate Park, San Francisco

It was still winter in Colorado in March 2023 when we took off to San Francisco on a California escape. The area had had a stressful winter of heavy rains and our trip was sandwiched in between two more storms. But we had a beautiful day for walking Golden Gate Park. 

Japanese Tea Garden, San Francisco

Plant Story - Lettuce, Lactuca sativa

Let us talk about lettuce.

garden lettuce, Lactuca sativa, in a garden

Lettuce is easily overlooked and yet it is one of the top ten vegetables, traded, grown, or eaten. Americans ate an average of 12.7 pounds of lettuce each in 2021 and 25.8 pounds per person in 2015. It is the world's most important salad crop. 

Plant Confusions: Hellebores, Helleborus and Veratrum species

The common name hellebore is confusing because three quite different plants are called hellebore or false hellebore. They're in the genera Helleborus, Veratrum and Adonis. Helleborus is just hellebore, Veratrum and Adonis are false hellebores, but of course sometimes the "false" is dropped. 

hellebore, Helleborus

All three are poisonous plants that have been used medicinally as purges, to cause vomiting and diarrhea. All three are sufficiently toxic as to be dangerous. 

Gardens and Natives: Colorado is Distinct from the East

I attended Landscaping with Colorado Native Plants conference in February. I came away very conscious of all the differences in gardening between our region and other places, especially the eastern U.S. If you want to grow Colorado natives, they recommended planting in a thick layer of crushed gravel (stone!), adding no fertilizer, washing off the potting soil to plant plants bare-rooted, and within a year, reducing water to once per week or once per month or not at all (that is, depending on rain and snow for water).  

 natural vegetation, Colorado grasslands

We imported our idea of landscape and garden mainly from settlers who came from Kansas or Iowa or Kentucky or Pennsylvania.

Plant Story: Christmas Rose, Lenten Rose, Helleborus

Hellebores, also called the Lenten roses and Christmas roses, Helleborus species, are early spring garden flowers. 

Lenten rose, Helleborus