One of the first steps you take when you are determining 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.

You should be able to estimate when to plant thunbergia by looking at the USDA zone info for Norristown.

Planting Calendar for Thunbergia

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

You can not plant thunbergia until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant thunbergia in Norristown 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. Any later than that and your thunbergia may not have a chance to fully mature. Starting your thunbergia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Norristown. In the coldest months of winter you can expect an average low temperature of 0°F.

It's important to remember that USDA zone info for Norristown is an average and the actual date of last frost is different every year. Half of the time in Norristown you get surprised by a frost after April 15 so be sure to be ready to protect your thunbergia in the event of a late frost.

USDA Zone Info for Norristown

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Norristown

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