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.

A way of estimating when it's the best time to plant oenothera is to refer to the USDA zone info for Ishpeming.

Planting Calendar for Oenothera

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

You can plant oenothera just a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant oenothera in Ishpeming 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. Any later than that and your oenothera may not have a chance to fully mature. You can get started a little bit earlier by starting your oenothera indoors.

Last Frost Date

On average the last frost is on May 15 in Ishpeming. You should expect an average low temperature of -25°F in the coldest months of winter.

It's important to remember that USDA zone info for Ishpeming may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Ishpeming last frost occurs after May 15 be ready to protect your oenothera in the event of a late frost.

USDA Zone Info for Ishpeming

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Ishpeming

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