The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when it's possible to plant lithospermum by referring to the USDA zone info for Stewartville.

Planting Calendar for Lithospermum

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

Lithospermum do not do well in cold weather which means that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lithospermum in Stewartville 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. Any later than that and your lithospermum may not have a chance to grow to maturity. Starting your lithospermum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Stewartville. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Stewartville is just an average the actual date of last frost is different every year. Half of the time in Stewartville you get surprised by a frost after May 15 so make sure that you are ready to cover your lithospermum in the event of one of those late frosts.

USDA Zone Info for Stewartville

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 Stewartville

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