One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Washington can be used to estimate when it's possible to plant blue throatwort.

Planting Calendar for Blue Throatwort

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

It's a bad idea to plant blue throatwort until after the last frost because they are not cold tolerant.

The earliest that you can plant blue throatwort 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 blue throatwort and expect a good harvest is probably August. Any later than that and your blue throatwort may not have a chance to really do well. You can get started a little bit earlier by starting your blue throatwort indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Washington. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Washington may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Washington there is a last frost after March 15 be ready to cover your blue throatwort 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.