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

In Cupertino you can figure out when to plant polygonums by checking out the USDA zone info.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You really shouldn't plant polygonums until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant polygonums in Cupertino is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant polygonums and expect a good harvest is probably September. Any later than that and your polygonums may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your polygonums 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.

Since the USDA zone info for Cupertino is just an average the actual date of last frost is different every year. Half of the time in Cupertino you get surprised by a frost after February 15 so always be ready to cover your polygonums in the event of a surprise 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 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 Cupertino

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