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

The USDA zone info for Napoleon can be used to determine when it's a good idea to plant lithospermum.

Planting Calendar for Lithospermum

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

It's probably not a good idea to plant lithospermum until after all chance of frost has passed because they require warm weather.

The earliest that you can plant lithospermum in Napoleon 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 grow to maturity. You can get started a few weeks earlier by starting your lithospermum indoors.

Last Frost Date

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

Keep in mind that USDA zone info for Napoleon is an average and the actual date of last frost is different every year. Half of the time in Napoleon it frosts late in the year after April 15 so make sure that you are ready to protect your lithospermum if you have one of those late frosts.

USDA Zone Info for Napoleon

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 Napoleon

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