When to Plant Rosemary in Frederick, CO

The USDA Zone info is a great tool for gardeners to help us determine 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 estimate when it's possible to plant rosemary in Frederick 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 tells us that you can get them planted much earlier than other frost tender plants.

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 Frederick 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 really do well. Starting your rosemary indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Frederick is not always accurate the actual date of last frost changes from year to year. Since half of the time in Frederick last frost occurs after April 15 be ready to cover your rosemary in the event of one of those late frosts.

USDA Zone Info for Frederick

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 Frederick

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