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 best time to plant oenothera in Portland can be estimated by referring to 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 tend to make it in moderate cold which tells us that you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant oenothera in Portland 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. If you wait 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

The average date of last frost is April 15 in Portland. It might get as low as 0°F during the coldest months of winter.

Keep in mind that USDA zone info for Portland may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Portland there is a last frost after April 15 so make sure that you are prepared to protect your oenothera in the event of a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 7a.

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

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

Plants to Grow in Portland

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