Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when to plant achillea is to use the USDA zone info for Chaska.

Planting Calendar for Achillea

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

Achillea can survive in cold weather which means that you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant achillea in Chaska 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 little bit earlier.

Last Frost Date

In Chaska the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Chaska is just an average the actual date of last frost will vary from year to year. Since half of the time in Chaska there is a last frost after May 15 be ready to protect your achillea in the event of one of those late frosts.

USDA Zone Info for Chaska

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 Chaska

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