One of the first steps you take when you are determining 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.

A common way of figuring out when to plant pyrethrum is to look at the USDA zone info for Bourbonnais.

Planting Calendar for Pyrethrum

Frost tolerance for pyrethrum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Pyrethrum do ok in some cold which tells us that you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant pyrethrum 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 pyrethrum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your pyrethrum may not have a chance to really do well. Starting your pyrethrum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Bourbonnais. In the coldest months of winter you can expect an average low temperature of -15°F.

Just be sure to remember that USDA zone info for Bourbonnais is not always accurate and the actual date of last frost is different every year. Half of the time in Bourbonnais there is a last frost after April 15 so just be sure to be ready to protect your pyrethrum 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.