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

By looking at the USDA zone info for Rhinelander you should be able to determine when it's a good idea 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 has passed.

Since blue throatwort do not do well in cold weather it's necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant blue throatwort in Rhinelander is May. However, you really should wait until June 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 grow to maturity. If you are starting your blue throatwort indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Rhinelander. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Rhinelander is an average the actual date of last frost changes from year to year. Half of the time in Rhinelander you get surprised by a frost after May 15 so make sure that you are prepared to protect your blue throatwort in the event of a surprise late frost.

USDA Zone Info for Rhinelander

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Rhinelander

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