When to Plant Thunbergia in Zone 1a

Before planting it is a good idea to find your USDA Zone info to figure out 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.

By reviewing the USDA zone info for Zone 1a you should be able to determine when you can plant thunbergia.


Planting Calendar for Thunbergia

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

It's not a good idea to plant thunbergia until after the last frost because they are not cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant thunbergia
Possibly ok, but a risky time to plant thunbergia
Probably not a good time to plant thunbergia

The earliest that you can plant thunbergia in Zone 1a is June. However, you really should wait until July if you don't want to take any chances.

The last month that you can plant thunbergia and expect a good harvest is probably July. You probably don't want to wait any later than that or else your thunbergia may not have a chance to grow to maturity. If you are starting your thunbergia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Zone 1a the average date of last frost happens on June 15. In the coldest months of winter you can expect an average low temperature of -60°F.

Since the USDA zone info for Zone 1a is just an average the actual date of last frost is different every year. Since half of the time in Zone 1a you get a frost after June 15 be ready to cover your thunbergia in the event of one of those late frosts.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)June 15
Average Date of First Frost (fall)July 15
Lowest Expected Low-60°F
Highest Expected Low-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in your other planting guides for Zone 1a.