The USDA Zone info is a great tool for gardeners to help us determine 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.

You should be able to determine when to plant four-o-clock flower by checking out the USDA zone info for Washington.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After the last frost.

Since four-o-clock flower are not cold tolerant you really should wait until after the last frost has passed before you can plant them.

The earliest that you can plant four-o-clock flower in Washington is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant four-o-clock flower and expect a good harvest is probably August. Any later than that and your four-o-clock flower may not have a chance to grow to maturity. You can get started a little bit earlier by starting your four-o-clock flower indoors.

Last Frost Date

In Washington the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Washington and it will vary from year to year. Half of the time in Washington you get surprised by a frost after March 15 so make sure that you are prepared to protect your four-o-clock flower in the event of a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Washington

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