One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. 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 Portland can be used to estimate when to plant verbena.

Planting Calendar for Verbena

Frost tolerance for verbena:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since verbena do ok in moderate cold you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant verbena 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 verbena and expect a good harvest is probably September. If you wait any later than that and your verbena may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your verbena indoors.

Last Frost Date

The average date of last frost is February 15 in Portland. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Portland is an average the actual date of last frost will vary from year to year. Half of the time in Portland you get a frost after February 15 so make sure that you are ready to protect your verbena if you have a surprise late frost.

USDA Zone Info for Portland

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 Portland

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