Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Herrin you should be able to figure out when you can plant oenothera.

Planting Calendar for Oenothera

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

Oenothera do well in moderate cold which tells us that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant oenothera in Herrin 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 oenothera and expect a good harvest is probably September. Any later than that and your oenothera may not have a chance to really do well. You can get started a few weeks earlier by starting your oenothera indoors.

Last Frost Date

The average date of last frost is April 15 in Herrin. It might get as low as -5°F during the coldest months of winter.

Always keep in mind that USDA zone info for Herrin is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Herrin it frosts late in the year after April 15 be ready to cover your oenothera in the event of a surprise late frost.

USDA Zone Info for Herrin

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Herrin

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