The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Berwyn it's a good idea to estimate when to plant yarrow.

Planting Calendar for Yarrow

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

Yarrow do well in a bit of cold which means that you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant yarrow 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 yarrow and expect a good harvest is probably September. Any later than that and your yarrow may not have a chance to grow to maturity. If you are starting your yarrow 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. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Berwyn is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Berwyn it frosts late in the year after April 15 so be sure to be ready to cover your yarrow in the event of one of those late frosts.

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.