The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when it's possible to plant blue throatwort is to look at the USDA zone info for Boston.

Planting Calendar for Blue Throatwort

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

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

The earliest that you can plant blue throatwort in Boston 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. If you wait any later than that and your blue throatwort may not have a chance to fully mature. 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 April 15 in Boston. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Boston is not always accurate the actual date of last frost is different every year. Since half of the time in Boston you get surprised by a frost after April 15 be ready to protect your blue throatwort if you have a surprise late frost.

USDA Zone Info for Boston

Here is the info for USDA Zone 6b.

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

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

Plants to Grow in Boston

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