When to Plant Cardinal Flower in Harlan, IA

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

A way of estimating when to plant cardinal flower is to examine the USDA zone info for Harlan.


Planting Calendar for Cardinal Flower

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

It's a bad idea to plant cardinal flower until after all chance of frost has passed because they are not cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant cardinal flower
Possibly ok, but a risky time to plant cardinal flower
Probably not a good time to plant cardinal flower

The earliest that you can plant cardinal flower in Harlan 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. Any later than that and 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 Harlan the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -20°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Harlan and it is different every year. Half of the time in Harlan there is a last frost after April 15 so make sure that you are ready to protect your cardinal flower in the event of one of those late frosts.

USDA Zone Info for Harlan

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Harlan

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