One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to estimate when it's a good idea to plant achillea by looking at the USDA zone info for Union.

Planting Calendar for Achillea

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

Achillea do ok in cold weather which tells us that you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant achillea in Union 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 really do well. Starting your achillea indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Union 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.

Remember that USDA zone info for Union is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Union last frost occurs after April 15 be ready to cover your achillea in the event of a surprise late frost.

USDA Zone Info for Union

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 Union

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