Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when it's the best time to plant thunbergia by using the USDA zone info for Palmer.

Planting Calendar for Thunbergia

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

Since thunbergia are not cold tolerant it's necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant thunbergia in Palmer is May. However, you really should wait until June 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 couple of weeks earlier by starting your thunbergia indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Palmer. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Palmer is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Palmer there is a last frost after May 15 be ready to protect your thunbergia in the event of a late frost.

USDA Zone Info for Palmer

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Palmer

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