The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant oenothera in Mercer Island should be determined by reviewing 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.

Since oenothera are moderately cold tolerant you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant oenothera in Mercer Island 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. You can get started a couple of weeks earlier by starting your oenothera indoors.

Last Frost Date

The average date of last frost is March 15 in Mercer Island. You should expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Mercer Island may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Mercer Island it frosts late in the year after March 15 so make sure that you are prepared to cover your oenothera if you have a late frost.

USDA Zone Info for Mercer Island

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 Mercer Island

You may be interested in your other planting guides for Mercer Island.