One of the best tools that you have as gardeners to help us estimate 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 Zone 4b should be read to figure out when it's a good idea to plant liatris.

Planting Calendar for Liatris

Frost tolerance for liatris:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant liatris much earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant liatris in Zone 4b is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant liatris and expect a good harvest is probably August. You probably don't want to wait any later than that or else your liatris may not have a chance to fully mature. If you are starting your liatris indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Zone 4b. You can expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4b is an average and the actual date of last frost is different every year. Half of the time in Zone 4b there is a last frost after May 15 so make sure that you are prepared to protect your liatris in the event of a surprise late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.