The USDA Zone info is a great tool for gardeners to help us estimate 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.

You should be able to determine when you can plant yarrow by referring to the USDA zone info for Glendive.

Planting Calendar for Yarrow

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

Yarrow do well in cold which tells us that you can plant them a quite a bit earlier than other frost tender plants.

The earliest that you can plant yarrow in Glendive 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. Any later than that and your yarrow may not have a chance to really do well. You can get started a few weeks earlier by starting your yarrow indoors.

Last Frost Date

On average the last frost is on May 15 in Glendive. You should expect an average low temperature of -30°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Glendive and it changes from year to year. Half of the time in Glendive you get a frost after May 15 so just be sure to be ready to protect your yarrow in the event of a surprise late frost.

USDA Zone Info for Glendive

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 Glendive

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