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.

A common way of making a decision about when you can plant hollyhocks is to use the USDA zone info for Columbia.

Planting Calendar for Hollyhocks

Frost tolerance for hollyhocks:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Hollyhocks are one of those plants that can tolerate a little bit of cold weather which means that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant hollyhocks 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 hollyhocks and expect a good harvest is probably September. Any later than that and your hollyhocks may not have a chance to really do well. You can get started a couple of weeks earlier by starting your hollyhocks indoors.

Last Frost Date

The average date of last frost is April 15 in Columbia. You can expect an average low temperature of -5°F in the coldest months of winter.

It's important to remember that USDA zone info for Columbia is an average and the actual date of last frost will vary from year to year. Half of the time in Columbia there is a last frost after April 15 so just be sure to be ready to cover your hollyhocks in the event of one of those late frosts.

USDA Zone Info for Columbia

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Columbia

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