One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Ann Arbor you can estimate when you can plant lithospermum by reviewing the USDA zone info.

Planting Calendar for Lithospermum

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

You can not plant lithospermum until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant lithospermum in Ann Arbor 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. Starting your lithospermum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ann Arbor. You can expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ann Arbor and it can change quite a bit from year to year. Since half of the time in Ann Arbor last frost occurs after April 15 be ready to cover your lithospermum in the event of a surprise late frost.

USDA Zone Info for Ann Arbor

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ann Arbor

You may be interested in your other planting guides for Ann Arbor.