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

The USDA zone info for Alamosa should be looked at to determine 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.

Rosemary are very cold tolerant which tells us that you can plant them much earlier than more sensitive plants.

The earliest that you can plant rosemary in Alamosa 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 grow to maturity. You can get started a couple of weeks earlier by starting your rosemary indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Alamosa. It might get as low as -25°F during the coldest months of winter.

Remember that USDA zone info for Alamosa is just an average and the actual date of last frost changes from year to year. Half of the time in Alamosa you get a frost after May 15 so be sure to be ready to cover your rosemary if you have one of those late frosts.

USDA Zone Info for Alamosa

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Alamosa

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