One of the first steps you take when you are estimating 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.

A common way of figuring out when you can plant lithospermum is to examine the USDA zone info for Douglas.

Planting Calendar for Lithospermum

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

You really shouldn't plant lithospermum until after the last frost because they do not do well in cold weather.

The earliest that you can plant lithospermum in Douglas 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 grow to maturity. Starting your lithospermum indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Douglas. In the coldest months of winter you can expect an average low temperature of 10°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Douglas and it changes from year to year. Half of the time in Douglas last frost occurs after March 15 so make sure that you are ready to cover your lithospermum in the event of a surprise late frost.

USDA Zone Info for Douglas

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Douglas

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