One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Miles City you can determine when you can plant yarrow by using 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.

Since yarrow are very cold tolerant you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant yarrow in Miles City is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant yarrow and expect a good harvest is probably August. If you wait any later than that and your yarrow may not have a chance to really do well. Starting your yarrow indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Miles City. You should expect an average low temperature of -30°F in the coldest months of winter.

It's important to remember that USDA zone info for Miles City is not always accurate and the actual date of last frost changes from year to year. Half of the time in Miles City you get a frost after May 15 so be sure to be ready to protect your yarrow in the event of one of those late frosts.

USDA Zone Info for Miles City

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Miles City

You may be interested in your other planting guides for Miles City.