Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In San Ramon you can estimate when it's the best time to plant tall phlox by looking at the USDA zone info.

Planting Calendar for Tall Phlox

Frost tolerance for tall phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant tall phlox a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant tall phlox in San Ramon is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant tall phlox and expect a good harvest is probably October. You probably don't want to wait any later than that or else your tall phlox may not have a chance to grow to maturity. If you are starting your tall phlox indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In San Ramon the average date of last frost happens on February 15. In the coldest months of winter you can expect an average low temperature of 25°F.

It's important to remember that USDA zone info for San Ramon may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in San Ramon it frosts late in the year after February 15 so be sure to be ready to protect your tall phlox if you have a late frost.

USDA Zone Info for San Ramon

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in San Ramon

You may be interested in your other planting guides for San Ramon.