The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 Zone 5b can be used to estimate when it's possible 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.

Since yarrow are very cold tolerant you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant yarrow in Zone 5b 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. You probably don't want to wait any later than that or else your yarrow may not have a chance to fully mature. You can get started a little bit earlier by starting your yarrow indoors.

Last Frost Date

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

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Zone 5b and it can change quite a bit from year to year. Since half of the time in Zone 5b there is a last frost after April 15 be ready to cover your yarrow in the event of a surprise late frost.

USDA Zone Info for Zone 5b

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 Zone 5b

You may be interested in your other planting guides for Zone 5b.