The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of estimating when it's the best time to plant lithospermum is to refer to the USDA zone info for Negaunee.

Planting Calendar for Lithospermum

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

It's probably a bad idea to plant lithospermum until after the last frost because they require warm weather.

The earliest that you can plant lithospermum in Negaunee 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. If you are starting your lithospermum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Negaunee. In the coldest months of winter you should expect an average low temperature of -20°F.

Since the USDA zone info for Negaunee is just an average the actual date of last frost will vary from year to year. Half of the time in Negaunee it frosts late in the year after April 15 so make sure that you are ready to protect your lithospermum if you have a surprise late frost.

USDA Zone Info for Negaunee

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Negaunee

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