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.

In Waterloo you can figure out when it's the best time to 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.

Yarrow are very cold tolerant which means that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant yarrow in Waterloo 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. Starting your yarrow indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Waterloo the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Waterloo is just an average and the actual date of last frost will vary from year to year. Half of the time in Waterloo you get surprised by a frost after April 15 so always be ready to cover your yarrow in the event of a surprise late frost.

USDA Zone Info for Waterloo

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 Waterloo

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