One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant periwinkles in Columbia should be determined by checking out the USDA zone info.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After the last frost.

You really shouldn't plant periwinkles until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant periwinkles in Columbia is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant periwinkles and expect a good harvest is probably August. Any later than that and your periwinkles may not have a chance to really do well. Starting your periwinkles indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Columbia. In the coldest months of winter you can expect an average low temperature of -10°F.

Remember that USDA zone info for Columbia is just an average and the actual date of last frost is different every year. Half of the time in Columbia you get a frost after April 15 so make sure that you are prepared to protect your periwinkles in the event of a late frost.

USDA Zone Info for Columbia

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 Columbia

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