When to Plant Primula in Willowbrook, IL

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant primula in Willowbrook can be figured out by looking at the USDA zone info.


Planting Calendar for Primula

Frost tolerance for primula: Very tolerant of frost.
When to plant: Up to 7 weeks before last frost.

Primula do ok in cold weather which means that you can plant them a lot earlier in the year than other frost tender plants.

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

The earliest that you can plant primula in Willowbrook is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant primula and expect a good harvest is probably September. You probably don't want to wait any later than that or else your primula may not have a chance to really do well. If you are starting your primula indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Willowbrook the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Willowbrook is just an average the actual date of last frost will vary from year to year. Half of the time in Willowbrook you get surprised by a frost after April 15 so be sure to be ready to cover your primula if you have one of those late frosts.

USDA Zone Info for Willowbrook

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-15°F
Highest Expected Low-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Willowbrook

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