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.

One way of making a decision about when it's the best time to plant rosemary is to use the USDA zone info for Ballwin.

Planting Calendar for Rosemary

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

Rosemary do ok in cold weather which tells us that you can plant them a lot earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant rosemary in Ballwin 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. Any later than that and your rosemary may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your rosemary indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Ballwin. You should expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that USDA zone info for Ballwin is an average and the actual date of last frost changes from year to year. Half of the time in Ballwin you get surprised by a frost after April 15 so make sure that you are prepared to protect your rosemary if you have a late frost.

USDA Zone Info for Ballwin

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ballwin

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