The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of getting a good idea when you can plant missouri primrose is to look at the USDA zone info for Caribou.

Planting Calendar for Missouri Primrose

Frost tolerance for missouri primrose:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Missouri Primrose can survive in moderate cold which tells us that you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant missouri primrose in Caribou is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant missouri primrose and expect a good harvest is probably August. If you wait any later than that and your missouri primrose may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your missouri primrose indoors.

Last Frost Date

In Caribou the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -30°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 Caribou and it changes from year to year. Since half of the time in Caribou you get a frost after May 15 be ready to protect your missouri primrose in the event of one of those late frosts.

USDA Zone Info for Caribou

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Caribou

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