One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of making a decision about when you can plant cardinal flower is to examine the USDA zone info for Onalaska.

Planting Calendar for Cardinal Flower

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

You really shouldn't plant cardinal flower until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant cardinal flower in Onalaska 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. If you wait any later than that and your cardinal flower may not have a chance to really do well. If you are starting your cardinal flower indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Onalaska. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Onalaska is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Onalaska it frosts late in the year after May 15 so be sure to be ready to cover your cardinal flower in the event of one of those late frosts.

USDA Zone Info for Onalaska

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 Onalaska

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