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 earliest that you can plant achillea in Berwyn can be figured out by referring to the USDA zone info.

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 a lot earlier in the year because they are very cold tolerant.

The earliest that you can plant achillea in Berwyn 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. If you are starting your achillea indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Berwyn the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Berwyn is just an average the actual date of last frost is different every year. Half of the time in Berwyn it frosts late in the year after April 15 so always be ready to cover your achillea in the event of a surprise late frost.

USDA Zone Info for Berwyn

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Berwyn

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