Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Groton can be looked at to estimate when it's a good idea to plant lithospermum.

Planting Calendar for Lithospermum

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

Since lithospermum are not cold tolerant you must wait until after the last frost has passed before you can plant them.

The earliest that you can plant lithospermum in Groton 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 fully mature. You can get started a little bit earlier by starting your lithospermum indoors.

Last Frost Date

In Groton the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Groton is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Groton last frost occurs after April 15 so make sure that you are ready to protect your lithospermum in the event of one of those late frosts.

USDA Zone Info for Groton

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Groton

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