One of the first steps you take when you are making a decision about 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.

You should be able to estimate when to plant liatris by using the USDA zone info for Stillwater.

Planting Calendar for Liatris

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

Liatris do ok in a bit of cold which tells us that you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant liatris in Stillwater 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. Starting your liatris indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Stillwater the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Stillwater is an average the actual date of last frost is different every year. Half of the time in Stillwater it frosts late in the year after May 15 so make sure that you are prepared to cover your liatris if you have a surprise late frost.

USDA Zone Info for Stillwater

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 Stillwater

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