One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of determining when it's a good idea to plant rosemary is to refer to the USDA zone info for Groton.

Planting Calendar for Rosemary

Frost tolerance for rosemary:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Rosemary can survive in a bit of cold which tells us that you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant rosemary in Groton 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 rosemary and expect a good harvest is probably September. If you wait any later than that and your rosemary may not have a chance to grow to maturity. If you are starting your rosemary indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Groton. It might get as low as -5°F during the coldest months of winter.

Always keep in mind that USDA zone info for Groton is an average and the actual date of last frost changes from year to year. Since half of the time in Groton it frosts late in the year after April 15 be ready to protect your rosemary if you have 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.