One of the best tools that you have as gardeners to help us estimate 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 estimating when it's possible to plant rosemary is to check out the USDA zone info for Walnut.

Planting Calendar for Rosemary

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

Since rosemary are one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant rosemary in Walnut is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant rosemary and expect a good harvest is probably October. If you wait any later than that and your rosemary may not have a chance to grow to maturity. You can get started a little bit earlier by starting your rosemary indoors.

Last Frost Date

On average the last frost has passed is on January 31 in Walnut. You can expect an average low temperature of 30°F in the coldest months of winter.

Remember that USDA zone info for Walnut is an average and the actual date of last frost is different every year. Half of the time in Walnut there is a last frost after January 31 so be sure to be ready to protect your rosemary in the event of a surprise late frost.

USDA Zone Info for Walnut

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Walnut

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