Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of getting a good idea when it's the best time to plant lithospermum is to look at the USDA zone info for Columbus.

Planting Calendar for Lithospermum

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

Lithospermum are not cold tolerant which tells us that it is important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lithospermum in Columbus 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. If you wait any later than that and your lithospermum may not have a chance to really do well. Starting your lithospermum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Columbus. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Columbus is just an average the actual date of last frost will vary from year to year. Since half of the time in Columbus you get a frost after April 15 be ready to cover your lithospermum in the event of one of those late frosts.

USDA Zone Info for Columbus

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 Columbus

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