When to Plant Rosemary in Louisville, CO

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of figuring out when it's possible to plant rosemary is to look at the USDA zone info for Louisville.


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 quite a bit of cold which tells us that you can plant them a lot earlier in the year than more sensitive 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 Louisville 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. If you wait any later than that and your rosemary may not have a chance to grow to maturity. Starting your rosemary indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Louisville the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

It's important to remember that USDA zone info for Louisville is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Louisville you get a frost after April 15 be ready to cover your rosemary if you have one of those late frosts.

USDA Zone Info for Louisville

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 Louisville

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