One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. 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 estimating when it's possible to plant achillea is to look at the USDA zone info for Plymouth.

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 Plymouth 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. Any later than that and your achillea may not have a chance to grow to maturity. Starting your achillea indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

It's important to remember that USDA zone info for Plymouth may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Plymouth last frost occurs after April 15 so always be ready to protect your achillea if you have a late frost.

USDA Zone Info for Plymouth

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Plymouth

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