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.

One way of estimating when it's possible to plant achillea is to use the USDA zone info for Somerville.

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 Somerville is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant achillea and expect a good harvest is probably September. You probably don't want to wait any later than that or else your achillea may not have a chance to grow to maturity. Starting your achillea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Somerville the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -5°F.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Somerville and it changes from year to year. Since half of the time in Somerville you get a frost after April 15 be ready to protect your achillea if you have a late frost.

USDA Zone Info for Somerville

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Somerville

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