Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to estimate when it's a good idea to plant thunbergia by looking at the USDA zone info for Salem.

Planting Calendar for Thunbergia

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

Since thunbergia require warm weather you need 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 Salem 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 fully mature. If you are starting your thunbergia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Salem. You should expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that USDA zone info for Salem may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Salem last frost occurs after April 15 so always be ready to cover your thunbergia in the event of one of those late frosts.

USDA Zone Info for Salem

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Salem

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