Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when it's a good idea to plant yarrow by using the USDA zone info for Blue Island.

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 Blue Island 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. If you wait any later than that and your yarrow may not have a chance to really do well. Starting your yarrow indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Blue Island. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Blue Island may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Blue Island it frosts late in the year after April 15 be ready to cover your yarrow in the event of one of those late frosts.

USDA Zone Info for Blue Island

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 Blue Island

You may be interested in your other planting guides for Blue Island.