One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant oenothera in Zone 3b can be figured out by reviewing the USDA zone info.

Planting Calendar for Oenothera

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

Oenothera are moderately cold tolerant which means that you can start planting them earlier than other frost tender plants.

The earliest that you can plant oenothera in Zone 3b 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 oenothera and expect a good harvest is probably August. If you wait any later than that and your oenothera may not have a chance to really do well. If you are starting your oenothera indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Zone 3b the average date of last frost happens on May 15. You should expect an average low temperature of -35°F in the coldest months of winter.

It's important to remember that USDA zone info for Zone 3b may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Zone 3b last frost occurs after May 15 so make sure that you are prepared to cover your oenothera if you have a surprise late frost.

USDA Zone Info for Zone 3b

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Zone 3b

You may be interested in your other planting guides for Zone 3b.