Before planting it is a good idea to find your USDA Zone info to estimate 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.

You should be able to estimate when it's possible to plant cardinal flower by using the USDA zone info for Austin.

Planting Calendar for Cardinal Flower

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

Cardinal Flower require warm weather which means that it is important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant cardinal flower in Austin is May. However, you really should wait until June 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. Any later than that and your cardinal flower may not have a chance to grow to maturity. Starting your cardinal flower indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Austin the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Austin may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Austin you get surprised by a frost after May 15 be ready to cover your cardinal flower in the event of a surprise late frost.

USDA Zone Info for Austin

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 Austin

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