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 estimate when it's the best time to plant lithospermum in Silvis by using the USDA zone info.

Planting Calendar for Lithospermum

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

Lithospermum require warm weather which tells us that it is important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lithospermum in Silvis 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. If you wait any later than that and 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 April 15 in Silvis. You can expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember that USDA zone info for Silvis is an average and the actual date of last frost changes from year to year. Half of the time in Silvis you get surprised by a frost after April 15 so be sure to be ready to protect your lithospermum if you have one of those late frosts.

USDA Zone Info for Silvis

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 Silvis

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