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.

A common way of determining when to plant achillea is to use the USDA zone info for Hillsdale.

Planting Calendar for Achillea

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

Since achillea are one of those plants that can tolerate quite a bit of cold weather you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant achillea in Hillsdale 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. Any later than that and your achillea may not have a chance to fully mature. If you are starting your achillea indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Hillsdale the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Hillsdale is not always accurate the actual date of last frost changes from year to year. Half of the time in Hillsdale you get surprised by a frost after April 15 so make sure that you are prepared to protect your achillea in the event of one of those late frosts.

USDA Zone Info for Hillsdale

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Hillsdale

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