When to Plant Coreopsis in Oswego, IL

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.

You can estimate when it's the best time to plant coreopsis in Oswego by looking at the USDA zone info.


Planting Calendar for Coreopsis

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

Coreopsis are moderately cold tolerant which tells us that you can get them planted earlier than other plants that might not handle the cold.

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

The earliest that you can plant coreopsis in Oswego 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 coreopsis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your coreopsis may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your coreopsis indoors.

Last Frost Date

The average date of last frost is April 15 in Oswego. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Oswego and it can change quite a bit from year to year. Half of the time in Oswego you get a frost after April 15 so be sure to be ready to cover your coreopsis in the event of a surprise late frost.

USDA Zone Info for Oswego

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 Oswego

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