The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of making a decision about when it's the best time to plant pyrethrum is to consult the USDA zone info for Dickinson.

Planting Calendar for Pyrethrum

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

You can plant pyrethrum a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant pyrethrum in Dickinson 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. If you wait any later than that and your pyrethrum may not have a chance to grow to maturity. Starting your pyrethrum indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Dickinson. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Dickinson is an average the actual date of last frost is different every year. Since half of the time in Dickinson you get a frost after May 15 be ready to cover your pyrethrum in the event of a surprise late frost.

USDA Zone Info for Dickinson

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Dickinson

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