Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 Roma should be reviewed to determine when you can plant oenothera.

Planting Calendar for Oenothera

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

Oenothera do well in moderate cold which means that you can plant them a little earlier in the year than other plants that might not handle the cold.

The earliest that you can plant oenothera in Roma is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant oenothera and expect a good harvest is probably October. Any later than that and your oenothera may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your oenothera indoors.

Last Frost Date

On average the last frost has passed is on February 15 in Roma. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Roma is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Roma you get surprised by a frost after February 15 so make sure that you are prepared to cover your oenothera if you have a surprise late frost.

USDA Zone Info for Roma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Roma

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