One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

You can figure out when it's possible to plant lithospermum in Roma 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 when the weather gets warmer.

Lithospermum are not cold tolerant which tells us that it's important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant lithospermum in Roma is March. However, you really should wait until April 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 grow to maturity. You can get started a little bit earlier by starting your lithospermum indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in Roma. You should expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that USDA zone info for Roma is an average and the actual date of last frost changes from year to year. Half of the time in Roma there is a last frost after February 15 so always be ready to cover your lithospermum in the event of a surprise late frost.

USDA Zone Info for Roma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Roma

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