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.

You should be able to figure out when you can plant regal geranium by reviewing the USDA zone info for Portland.

Planting Calendar for Regal Geranium

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

Regal Geranium can survive in mild cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

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

Since the USDA zone info for Portland may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Portland last frost occurs after February 15 be ready to cover your regal geranium in the event of a 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.