The USDA Zone info is a great tool for gardeners to help us estimate your gardening 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 Portola Valley it's a good idea to figure out when it's the best time to plant cardinal flower.

Planting Calendar for Cardinal Flower

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

Cardinal Flower do not do well in cold weather which tells us that it is necessary to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant cardinal flower in Portola Valley is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant cardinal flower and expect a good harvest is probably September. If you wait any later than that and your cardinal flower may not have a chance to really do well. Starting your cardinal flower indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on January 31 in Portola Valley. You can expect an average low temperature of 30°F in the coldest months of winter.

Always keep in mind that USDA zone info for Portola Valley is just an average and the actual date of last frost will vary from year to year. Since half of the time in Portola Valley last frost occurs after January 31 be ready to protect your cardinal flower if you have one of those late frosts.

USDA Zone Info for Portola Valley

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Portola Valley

You may be interested in your other planting guides for Portola Valley.