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

By reviewing the USDA zone info for Waterloo it's possible to estimate when to plant achillea.

Planting Calendar for Achillea

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

You can plant achillea earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant achillea 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 achillea and expect a good harvest is probably September. If you wait any later than that and your achillea may not have a chance to fully mature. Starting your achillea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Waterloo. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind that USDA zone info for Waterloo is just an average and the actual date of last frost changes from year to year. Half of the time in Waterloo last frost occurs after April 15 so always be ready to protect your achillea if you have one of those late frosts.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Waterloo

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