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.

The USDA zone info for Corvallis can be reffered to in order to estimate when it's possible to 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.

Since thunbergia do not do well in cold weather it's important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Corvallis 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. Starting your thunbergia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Corvallis. It might get as low as 15°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Corvallis may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Corvallis you get a frost after March 15 be ready to cover your thunbergia in the event of a late frost.

USDA Zone Info for Corvallis

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 Corvallis

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