Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when you can plant calliopsis is to examine the USDA zone info for Flagstaff.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost.

You should not plant calliopsis until after the last frost when the weather gets warmer because they require warm weather.

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

The last month that you can plant calliopsis and expect a good harvest is probably August. If you wait any later than that and your calliopsis may not have a chance to really do well. Starting your calliopsis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Flagstaff. It might get as low as -10°F during the coldest months of winter.

Remember that USDA zone info for Flagstaff is just an average and the actual date of last frost changes from year to year. Half of the time in Flagstaff there is a last frost after April 15 so be sure to be ready to cover your calliopsis if you have a late frost.

USDA Zone Info for Flagstaff

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 Flagstaff

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