The USDA Zone info is a great tool for gardeners to help us figure out 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.

The earliest that you can plant thunbergia in Sonora should be estimated by using the USDA zone info.

Planting Calendar for Thunbergia

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

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

The earliest that you can plant thunbergia 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 thunbergia and expect a good harvest is probably September. Any later than that and your thunbergia may not have a chance to grow to maturity. You can get started a little bit earlier by starting your thunbergia indoors.

Last Frost Date

In Sonora the average date of last frost happens on February 15. In the coldest months of winter you can expect an average low temperature of 20°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 Sonora and it can change quite a bit from year to year. Since half of the time in Sonora there is a last frost after February 15 be ready to cover your thunbergia if you have a surprise 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.