One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Oak Brook you can estimate when it's possible to plant liatris by reviewing the USDA zone info.

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 frost tender plants.

The earliest that you can plant liatris in Oak Brook 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. Any later than that and your liatris may not have a chance to really do well. Starting your liatris indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Oak Brook. You should expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Oak Brook is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Oak Brook it frosts late in the year after April 15 so just be sure to be ready to cover your liatris if you have a surprise late frost.

USDA Zone Info for Oak Brook

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 Oak Brook

You may be interested in your other planting guides for Oak Brook.