Archive | Gardener’s Notebook


Plant a Tree Collard
Now is the time!

By Joshua Burman Thayer


As winter brings shorter days and cooler temperatures, our gardens enjoy a reprieve from the dryness of summer. More moisture comes not only from winter rains, but also from condensation as the dew point rises. The dew point is the atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense, causing dew to form.

But there’s a downside for gardeners. Cooler soil temperature and the higher dew point can lead to powdery mildew and botrytis mold creeping in among our late season grapes, tomatoes, and other lingering fruits and vegetables. That’s why this is a good time to focus on a different set of plants, the ones we refer to as cool-season crops.  

Among my favorite cool-season additions to the garden is the tree collard. This unique member of the cabbage family (Brassicaceae) is able to continue growing season after season as a perennial, climbing upward each year toward the sky. If you have ever wondered about adding a perennial crop inside or near your raised beds full of annuals, tree collards are a good choice. Here are some fun ways to incorporate them into your cool-season beds:

Plant the Northern Boundary

Tree collards can grow to seven feet tall, which in a small urban raised bed could mean shading out other plants looking for sunlight.… Read More

Continue Reading

Gardener’s Notebook

Pomegranate Pizzazz

Ruby red pomegranate seeds enliven our salads, meats, sauces, and desserts with their brilliant color and tart-sweet flavor. Pomegranate trees and shrubs (Punica granatum) grow easily here in the Bay Area and are best planted between September and November. This is also when the fruits are harvested. 

Pomegranate lovers owe thanks to botanist Gregory M. Levin, author of Pomegranate Roads: A Soviet Botanist’s Exile from Eden, who collected more than 1,000 specimens from the vast dry slopes of Central Asia and brought them back to his Soviet research station in Garrigala, Turkmenistan. Levin propagated plants from wild stock and perpetuated several of the varieties we like to plant here in the Bay Area including the Parfianka variety, which he donated to UC Davis as the
Soviet Union collapsed. 

Pomegranate bushes are easy to grow, and since they need water only once per week, we can practically dry farm these rugged shrubs in the gaps between other plantings. Follow these steps for planting and caring for your pomegranate bushes:

  • Start from a cutting or nursery plant and chose a sunny, warm spot for your bush. 
  • Plant before winter sets in. The young plants can tolerate wind, but once there’s been a week of rain, the soil becomes difficult to work.
Read More
Continue Reading

Gardener’s Notebook

Growing Food Near Native Oaks


Is it possible to grow perennial food plants near native oaks? 
Yes, with the right plants and methods.

Here in Northern California, we are blessed with many stoic and picturesque native oaks. Quercus agrifolia (coastal live oak), Quercus lobata (valley oak), and Quercus douglasii (blue oak) are all found in this bioregion. While sudden oak death and other oak ailments may be a result of anthropogenic (man-made) influences, fear not: By following some simple rules and planting specially adapted native plants, you can foster life under and around your oaks.

Drip Line Denotes Microclimate

pink flowering currantOur California oaks have evolved to thrive in dry soil throughout our long summer drought. While those conditions would seem to discourage plant growth, an intact oak savanna ecosystem displays a diversity of plants growing in the “skirts” of the oak trees, due to the increased moisture present in areas around the tree where rain (and accumulated fog) drips from the branches. Called the “drip line,” this is a sweet spot for many of the oak savanna native plant species, and gardeners can put it to good use. 

In my consulting work with homeowners and on ranches, one of the main mistakes I see is that irrigation is installed too close to the drip line of the oak.… Read More

Continue Reading