One of the best tools that you have as gardeners to help us figure out 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 USDA zone info for Frederick should be looked at to determine when it's possible to plant oenothera.

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 Frederick 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. You probably don't want to wait any later than that or else your oenothera may not have a chance to fully mature. 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

On average the last frost when the weather gets warmer is on April 15 in Frederick. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Frederick 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 Frederick there is a last frost after April 15 be ready to cover your oenothera in the event of a late frost.

USDA Zone Info for Frederick

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 Frederick

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