The USDA Zone info is a great tool for gardeners to help us determine 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.

By looking at the USDA zone info for Vernon Hills you should be able to determine when to plant lithospermum.

Planting Calendar for Lithospermum

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

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

The earliest that you can plant lithospermum in Vernon Hills 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 really do well. You can get started a few weeks earlier by starting your lithospermum indoors.

Last Frost Date

The average date of last frost is April 15 in Vernon Hills. It might get as low as -15°F during the coldest months of winter.

It's important to remember that USDA zone info for Vernon Hills is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Vernon Hills it frosts late in the year after April 15 be ready to cover your lithospermum in the event of a late frost.

USDA Zone Info for Vernon Hills

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Vernon Hills

You may be interested in your other planting guides for Vernon Hills.