The USDA Zone info is a great tool for gardeners to help us figure out 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.

In Issaquah you can determine when you can plant yarrow by checking out the USDA zone info.

Planting Calendar for Yarrow

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

You can plant yarrow quite a bit earlier in the year because they are very cold tolerant.

The earliest that you can plant yarrow in Issaquah 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 fully mature. You can get started a few weeks earlier by starting your yarrow indoors.

Last Frost Date

On average the last frost is on March 15 in Issaquah. In the coldest months of winter you should expect an average low temperature of 15°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Issaquah and it will vary from year to year. Since half of the time in Issaquah it frosts late in the year after March 15 be ready to protect your yarrow in the event of a surprise late frost.

USDA Zone Info for Issaquah

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Issaquah

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