One of the first steps you take when you are making a decision about 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 earliest that you can plant thunbergia in Washington should be figured out by using the USDA zone info.

Planting Calendar for Thunbergia

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

It's probably not a good idea to plant thunbergia until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant thunbergia in Washington 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. If you wait any later than that and your thunbergia may not have a chance to really do well. You can get started a little bit earlier by starting your thunbergia indoors.

Last Frost Date

The average date of last frost is March 15 in Washington. In the coldest months of winter you can expect an average low temperature of 10°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Washington and it can change quite a bit from year to year. Half of the time in Washington last frost occurs after March 15 so be sure to be ready to cover your thunbergia if you have a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Washington

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