One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant periwinkles in Columbia should be estimated by using the USDA zone info.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since periwinkles are not cold tolerant it's important to wait until after the last frost has passed before you can plant them.

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 fully mature. If you are starting your periwinkles indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Columbia and it is different every year. Half of the time in Columbia it frosts late in the year after March 15 so make sure that you are ready to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Columbia

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Columbia

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