One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant thunbergia in Corona should be figured out by reviewing the USDA zone info.

Planting Calendar for Thunbergia

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

Thunbergia do not do well in cold weather which means that you have to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Corona 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 really do well. Starting your thunbergia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Corona. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Corona is just an average the actual date of last frost is different every year. Half of the time in Corona last frost occurs after February 15 so make sure that you are prepared to cover your thunbergia in the event of one of those late frosts.

USDA Zone Info for Corona

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 Corona

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