The USDA Zone info is a great tool for gardeners to help us figure out 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 will be able to estimate when you can plant hollyhocks by referring to 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.

Since hollyhocks are moderately cold tolerant you can plant them a little bit earlier in the year than other frost tender 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. If you wait any later than that and your hollyhocks may not have a chance to fully mature. Starting your hollyhocks indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Columbia. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Columbia is just an average the actual date of last frost is different every year. Half of the time in Columbia it frosts late in the year after April 15 so always be ready to protect your hollyhocks if you have a late frost.

USDA Zone Info for Columbia

Here is the info for USDA Zone 7a.

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

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

Plants to Grow in Columbia

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