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 can figure out when it's the best time to plant yarrow in Hannibal by checking out 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.

You can plant yarrow much earlier in the year because they are very cold tolerant.

The earliest that you can plant yarrow in Hannibal 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 yarrow and expect a good harvest is probably September. You probably don't want to wait any later than that or else your yarrow may not have a chance to really do well. If you are starting your yarrow indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Hannibal. You can expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that USDA zone info for Hannibal may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Hannibal it frosts late in the year after April 15 be ready to cover your yarrow if you have a surprise late frost.

USDA Zone Info for Hannibal

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 Hannibal

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