One of the first steps you take when you are getting a good idea 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.

The USDA zone info for Wausau should be used to determine when you can plant pyrethrum.

Planting Calendar for Pyrethrum

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

Pyrethrum can survive in some cold which tells us that you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant pyrethrum in Wausau 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 pyrethrum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your pyrethrum may not have a chance to really do well. You can get started a little bit earlier by starting your pyrethrum indoors.

Last Frost Date

In Wausau the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Wausau and it changes from year to year. Half of the time in Wausau last frost occurs after May 15 so make sure that you are ready to protect your pyrethrum in the event of a late frost.

USDA Zone Info for Wausau

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 Wausau

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