Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to estimate when it's possible to plant oenothera by looking at the USDA zone info for Ephraim.

Planting Calendar for Oenothera

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

Since oenothera are moderately cold tolerant you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant oenothera in Ephraim 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. If you are starting your oenothera indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ephraim. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Ephraim is just an average the actual date of last frost changes from year to year. Half of the time in Ephraim you get surprised by a frost after April 15 so make sure that you are prepared to protect your oenothera in the event of a late frost.

USDA Zone Info for Ephraim

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ephraim

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