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.

A way of making a decision about when you can plant oenothera is to examine the USDA zone info for Gresham.

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 a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant oenothera in Gresham 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 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

In Gresham the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Gresham is not always accurate the actual date of last frost changes from year to year. Half of the time in Gresham you get surprised by a frost after March 15 so make sure that you are prepared to cover your oenothera if you have a surprise late frost.

USDA Zone Info for Gresham

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Gresham

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