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.

The USDA zone info for Columbia should be looked at to figure out when to plant yarrow.

Planting Calendar for Yarrow

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

Since yarrow do well in cold you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant yarrow in Columbia 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. Any later than that and your yarrow may not have a chance to fully mature. You can get started a little bit earlier by starting your yarrow indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Columbia. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Columbia may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Columbia it frosts late in the year after March 15 be ready to cover your yarrow in the event of one of those late frosts.

USDA Zone Info for Columbia

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Columbia

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