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.

You should be able to figure out when it's possible to plant achillea by referring to the USDA zone info for Litchfield.

Planting Calendar for Achillea

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

Since achillea are very cold tolerant you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant achillea in Litchfield 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 really do well. Starting your achillea indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Litchfield. It might get as low as -25°F during the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Litchfield and it is different every year. Half of the time in Litchfield last frost occurs after May 15 so always be ready to cover your achillea if you have a surprise late frost.

USDA Zone Info for Litchfield

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 Litchfield

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