The USDA Zone info is a great tool for gardeners to help us figure out 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.

The USDA zone info for Flagstaff can be looked at to determine when it's a good idea to plant bidens.

Planting Calendar for Bidens

Frost tolerance for bidens:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since bidens are not cold tolerant you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant bidens 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 bidens and expect a good harvest is probably August. You probably don't want to wait any later than that or else your bidens may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your bidens indoors.

Last Frost Date

The average date of last frost is April 15 in Flagstaff. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Flagstaff is just an average the actual date of last frost changes from year to year. Half of the time in Flagstaff it frosts late in the year after April 15 so be sure to be ready to protect your bidens in the event of a surprise 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.