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.

You can determine when it's possible to plant lithospermum in Superior by checking out the USDA zone info.

Planting Calendar for Lithospermum

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

You really shouldn't plant lithospermum until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant lithospermum in Superior is May. However, you really should wait until June 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 grow to maturity. You can get started a couple of weeks earlier by starting your lithospermum indoors.

Last Frost Date

The average date of last frost is May 15 in Superior. It might get as low as -25°F during the coldest months of winter.

Keep in mind that USDA zone info for Superior is not always accurate and the actual date of last frost is different every year. Since half of the time in Superior it frosts late in the year after May 15 be ready to protect your lithospermum if you have a surprise late frost.

USDA Zone Info for Superior

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Superior

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