One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. 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 Sonora can be read to determine when it's the best time to plant blue throatwort.

Planting Calendar for Blue Throatwort

Frost tolerance for blue throatwort:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since blue throatwort do not do well in cold weather you really should wait until after the last frost before you can plant them.

The earliest that you can plant blue throatwort in Sonora 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 blue throatwort and expect a good harvest is probably September. If you wait any later than that and your blue throatwort may not have a chance to really do well. Starting your blue throatwort indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Sonora the average date of last frost happens on February 15. You can expect an average low temperature of 20°F in the coldest months of winter.

Since the USDA zone info for Sonora is just an average the actual date of last frost will vary from year to year. Half of the time in Sonora last frost occurs after February 15 so make sure that you are prepared to protect your blue throatwort if you have a late frost.

USDA Zone Info for Sonora

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Sonora

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