The USDA Zone info is a great tool for gardeners to help us determine 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.

By using the USDA zone info for Oak Brook you will be able to determine when to plant california poppy.

Planting Calendar for California Poppy

Frost tolerance for california poppy:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since california poppy do ok in moderate cold you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant california poppy in Oak Brook 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 california poppy and expect a good harvest is probably August. You probably don't want to wait any later than that or else your california poppy may not have a chance to grow to maturity. If you are starting your california poppy indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Oak Brook the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Oak Brook is not always accurate the actual date of last frost is different every year. Half of the time in Oak Brook there is a last frost after April 15 so always be ready to protect your california poppy if you have one of those late frosts.

USDA Zone Info for Oak Brook

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 Oak Brook

You may be interested in your other planting guides for Oak Brook.