One of the first steps you take when you are figuring out your gardening schedule is find your 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 Bourbonnais can be used to figure out when 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.

Since liatris do well in cold you can plant them earlier in the year than other plants that might not handle the cold.

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

The last month that you can plant liatris and expect a good harvest is probably September. You probably don't want to wait any later than that or else your liatris may not have a chance to really do well. You can get started a few weeks earlier by starting your liatris indoors.

Last Frost Date

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

Since the USDA zone info for Bourbonnais is not always accurate the actual date of last frost will vary from year to year. Half of the time in Bourbonnais last frost occurs after April 15 so always be ready to protect your liatris if you have a surprise late frost.

USDA Zone Info for Bourbonnais

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Bourbonnais

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