The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Whittier should be reviewed to determine when you can plant blue throatwort.

Planting Calendar for Blue Throatwort

Frost tolerance for blue throatwort:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's probably not a good idea to plant blue throatwort until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant blue throatwort in Whittier 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 blue throatwort and expect a good harvest is probably September. Any later than that and your blue throatwort may not have a chance to fully mature. Starting your blue throatwort indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is January 31 in Whittier. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for Whittier may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Whittier last frost occurs after January 31 so make sure that you are ready to cover your blue throatwort in the event of one of those late frosts.

USDA Zone Info for Whittier

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 Whittier

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