Gardening Resources

The Washington Square Neighborhood is full of avid gardeners and plant owners. Here are some resources to help you care for your gardens, indoor and out.  Please ask at the next WSNA meeting or on Next Door how to join the discussion group.

Area Notes

  • USDA: Zone 10a
  • Sunset Zone: 21
    The combination of weather influences described for Zone 20 applies to Zone 21 as well. Your garden can be in ocean air or a high fog one day and in a mass of interior air (perhaps a drying Santa Ana wind from the desert) the next day. Because temperatures rarely drop very far below 30°F (–1°C), this is fine citrusgrowing country. At the same time, Zone 21 is also the mildest zone that gets sufficient winter chilling for most forms of lilacs and certain other chill-loving plants. Extreme lows—the kind you see once every 10 or 20 years—in Zone 21 average 28 to 25°F (–2 to –4°C).All-time record lows in the zone were 27 to 17°F (–3 to –8°C). (via
  • Bioregion: South Coast, Cismontane coastal sage scrub / chaparral
  • Annual Precipitation: 21.27″
  • Summer Precipitation: 0.52″
  • Coldest Month Temp: Avg. 53.60° F, around 67° F day and 47° F night, 1990 low 26°F
  • Hottest Month Temp: Avg. 78.24° F, around 91° F day and 65° F night, 2018 high 113 °F
  • Humidity: 3.52 – 23.78 vpd
  • Elevation: Northwest corner of park – 299.00 m / 980.97 ft,  Intersection of Mountain and Lake – 277.00 m / 908.79 ft
  • Day Length: 10hrs to 14.5hrs  (sun angles)
  • Hot Season: March-October
  • Cool Season: October-March
  • Growing Guide:
  • Last Frost: infrequent, not after Jan 31
  • First Frost: infrequent, not before Dec 21
  • No. of Frost Free Days* at 32° F or higher: 365

More sources:

California Natives

Theodore Payne Foundation has classes, books, plants and an online database.

Look up what’s native to our area on

Food Gardening

There are many styles of food gardens, including

Tips for Bringing New Plants Home or Indoors for the Winter

While we don’t have to bring as many plants indoors over the winter as some of our more northerly neighbors, the tips for bringing plants in for the winter a similar to tips for bringing new plants home.  You can find details at the Penn State Extension and Vermont Extensionwebsites, but the general tips include

  1. Look for bugs and bug damage
  2. Completely rinse and wipe down plant, soak if applicable
  3. Keep isolated from other plants temporarily to keep an eye on it

Plant Swap Tips

  • Bring healthy plants.
  • Label the plants if you can. Scientific name if you know it. Your contact information could help the new owner, too. Pencil on a popsicle stick works great.
  • If you water the plant ahead of time, put it in a sealed plastic bag. If it is a big plant consider holding off to prevent it from being too heavy to move.

Where to Buy Plants

Selected nurseries recommended by residents in no particular order.

Lincoln Avenue Nursery

Theodore Payne Foundation

Bellafontaine Nursery 

San Gabriel Valley Nursery

Folia Collective

Armstrong Nurseries