One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for San Bernardino should be reffered to in order to estimate when it's the best time to plant thunbergia.

Planting Calendar for Thunbergia

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

Since thunbergia are not cold tolerant it is necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant thunbergia in San Bernardino 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. If you wait any later than that and your thunbergia may not have a chance to fully mature. You can get started a little bit earlier by starting your thunbergia indoors.

Last Frost Date

In San Bernardino the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for San Bernardino may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in San Bernardino there is a last frost after February 15 so be sure to be ready to protect your thunbergia in the event of one of those late frosts.

USDA Zone Info for San Bernardino

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 San Bernardino

You may be interested in your other planting guides for San Bernardino.