Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when to plant cardinal flower by looking at the USDA zone info for Phoenix.

Planting Calendar for Cardinal Flower

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

It's probably a bad idea to plant cardinal flower until after the last frost because they are not cold tolerant.

The earliest that you can plant cardinal flower in Phoenix 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 cardinal flower and expect a good harvest is probably August. You probably don't want to wait any later than that or else your cardinal flower may not have a chance to grow to maturity. If you are starting your cardinal flower indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Phoenix and it changes from year to year. Since half of the time in Phoenix last frost occurs after March 15 be ready to protect your cardinal flower in the event of a late frost.

USDA Zone Info for Phoenix

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Phoenix

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