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

The first opportunity to plant thunbergia in Boulder City can be estimated by referring to the USDA zone info.

Planting Calendar for Thunbergia

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

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

The earliest that you can plant thunbergia in Boulder City 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 couple of weeks earlier by starting your thunbergia indoors.

Last Frost Date

The average date of last frost is February 15 in Boulder City. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Boulder City and it changes from year to year. Half of the time in Boulder City it frosts late in the year after February 15 so be sure to be ready to cover your thunbergia in the event of a surprise late frost.

USDA Zone Info for Boulder City

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 Boulder City

You may be interested in your other planting guides for Boulder City.