When to Plant Tall Phlox in Cupertino, CA

Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By reviewing the USDA zone info for Cupertino it's a good idea to estimate when it's a good idea to plant tall phlox.


Planting Calendar for Tall Phlox

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

Since tall phlox are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant tall phlox
Possibly ok, but a risky time to plant tall phlox
Probably not a good time to plant tall phlox

The earliest that you can plant tall phlox in Cupertino 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. Any later than that and your tall phlox may not have a chance to really do well. You can get started a couple of weeks earlier by starting your tall phlox indoors.

Last Frost Date

In Cupertino 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.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Cupertino and it will vary from year to year. Half of the time in Cupertino there is a last frost after February 15 so make sure that you are ready to protect your tall phlox in the event of a late frost.

USDA Zone Info for Cupertino

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 Low25°F
Highest Expected Low30°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 Cupertino

You may be interested in your other planting guides for Cupertino.