The USDA Zone info is a great tool for gardeners to help us determine 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 best time to plant thunbergia in Columbia can be determined 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 has passed.

You should not plant thunbergia until after the last frost because they are not cold tolerant.

The earliest that you can plant thunbergia in Columbia is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant thunbergia and expect a good harvest is probably August. You probably don't want to wait any later than that or else 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 Columbia the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 15°F.

Since the USDA zone info for Columbia is not always accurate the actual date of last frost will vary from year to year. Half of the time in Columbia you get surprised by a frost after March 15 so make sure that you are prepared to protect your thunbergia if you have a surprise late frost.

USDA Zone Info for Columbia

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Columbia

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