When to Plant Rosemary in Mason City, IA

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.

You can determine when you can plant rosemary in Mason City by looking at the USDA zone info.


Planting Calendar for Rosemary

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

Rosemary do well in cold which means that you can start planting them much earlier than other plants that might not handle the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant rosemary
Possibly ok, but a risky time to plant rosemary
Probably not a good time to plant rosemary

The earliest that you can plant rosemary in Mason City 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 little bit earlier by starting your rosemary indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Mason City. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Mason City is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Mason City there is a last frost after April 15 be ready to protect your rosemary if you have a late frost.

USDA Zone Info for Mason City

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Mason City

You may be interested in your other planting guides for Mason City.