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.

The USDA zone info for Plymouth should be read to figure out when to plant achillea.

Planting Calendar for Achillea

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

Since achillea do well in cold you can plant them earlier in the year than other frost tender plants.

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. If you wait any later than that and your achillea may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your achillea indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Plymouth. It might get as low as -15°F during the coldest months of winter.

Keep in mind that USDA zone info for Plymouth is not always accurate and the actual date of last frost changes from year to year. Half of the time in Plymouth you get a frost after April 15 so be sure to be ready to protect your achillea in the event of one of those late frosts.

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.