One of the best tools that you have as gardeners to help us estimate 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.

One way of making a decision about when to plant lithospermum is to refer to the USDA zone info for Columbia.

Planting Calendar for Lithospermum

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

You should not plant lithospermum until after the last frost because they require warm weather.

The earliest that you can plant lithospermum 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 lithospermum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lithospermum may not have a chance to fully mature. You can get started a few weeks earlier by starting your lithospermum indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Columbia. In the coldest months of winter you should expect an average low temperature of -5°F.

Just be sure to remember that USDA zone info for Columbia may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Columbia last frost occurs after April 15 so just be sure to be ready to protect your lithospermum if you have a late frost.

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.