The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to figure out when it's possible to plant lithospermum by looking at the USDA zone info for Walnut.

Planting Calendar for Lithospermum

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

Since lithospermum are not cold tolerant you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant lithospermum in Walnut is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant lithospermum and expect a good harvest is probably September. If you wait any later than that and your lithospermum may not have a chance to really do well. If you are starting your lithospermum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Walnut. In the coldest months of winter you can expect an average low temperature of 30°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Walnut and it is different every year. Half of the time in Walnut there is a last frost after January 31 so make sure that you are ready to protect your lithospermum if you have a late frost.

USDA Zone Info for Walnut

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Walnut

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