One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By using the USDA zone info for Zone 1b it's a good idea to figure out when you can plant lithospermum.

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 important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lithospermum in Zone 1b is June. However, you really should wait until July if you don't want to take any chances.

The last month that you can plant lithospermum and expect a good harvest is probably July. 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 little bit earlier.

Last Frost Date

In Zone 1b the average date of last frost happens on June 15. You can expect an average low temperature of -55°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Zone 1b is an average and the actual date of last frost changes from year to year. Half of the time in Zone 1b you get surprised by a frost after June 15 so just be sure to be ready to cover your lithospermum in the event of a surprise late frost.

USDA Zone Info for Zone 1b

Here is the info for USDA Zone 1b.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-55°F
Highest Expected Low	-50°F

This means that on a really cold year, the coldest it will get is -55°F. On most years you should be prepared to experience lows near -50°F.

Plants to Grow in Zone 1b

You may be interested in your other planting guides for Zone 1b.