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

The earliest that you can plant yarrow in Hillsboro should be determined by looking at 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.

Yarrow do well in cold which means that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant yarrow in Hillsboro 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 fully mature. 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 Hillsboro 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.

It's important to remember that USDA zone info for Hillsboro is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Hillsboro there is a last frost after April 15 so just be sure to be ready to cover your yarrow if you have one of those late frosts.

USDA Zone Info for Hillsboro

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 Hillsboro

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