The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when it's a good idea to plant achillea by reviewing the USDA zone info for Stewartville.

Planting Calendar for Achillea

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

You can plant achillea much earlier in the year because they do well in cold.

The earliest that you can plant achillea in Stewartville 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 achillea and expect a good harvest is probably August. If you wait any later than that and your achillea may not have a chance to grow to maturity. If you are starting your achillea indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Stewartville. In the coldest months of winter you should expect an average low temperature of -25°F.

Just be sure to remember that USDA zone info for Stewartville is not always accurate and the actual date of last frost changes from year to year. Half of the time in Stewartville you get surprised by a frost after May 15 so be sure to be ready to protect your achillea if you have one of those late frosts.

USDA Zone Info for Stewartville

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 Stewartville

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