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

By using the USDA zone info for Bolingbrook it's a good idea to estimate when it's the best time to plant rosemary.

Planting Calendar for Rosemary

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

Since rosemary do well in cold you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant rosemary in Bolingbrook 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 fully mature. 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

The average date of last frost is April 15 in Bolingbrook. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Bolingbrook and it can change quite a bit from year to year. Since half of the time in Bolingbrook you get surprised by a frost after April 15 be ready to cover your rosemary in the event of a late frost.

USDA Zone Info for Bolingbrook

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Bolingbrook

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