One of the best tools that you have as gardeners to help us estimate 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.

By looking at the USDA zone info for Bismarck you will be able to figure out when it's possible 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 are one of those plants that can tolerate quite a bit of cold weather you can plant them a lot earlier in the year than other frost tender plants.

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

The last month that you can plant rosemary and expect a good harvest is probably August. You probably don't want to wait any later than that or else 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

In Bismarck the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Bismarck and it is different every year. Half of the time in Bismarck you get surprised by a frost after May 15 so make sure that you are ready to cover your rosemary if you have a surprise late frost.

USDA Zone Info for Bismarck

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°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 -25°F.

Plants to Grow in Bismarck

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