The USDA Zone info is a great tool for gardeners to help us figure out 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 can determine when it's possible to plant tropical hibiscus in Portland by looking at the USDA zone info.

Planting Calendar for Tropical Hibiscus

Frost tolerance for tropical hibiscus:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's not a good idea to plant tropical hibiscus until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant tropical hibiscus in Portland is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant tropical hibiscus and expect a good harvest is probably September. You probably don't want to wait any later than that or else your tropical hibiscus may not have a chance to fully mature. If you are starting your tropical hibiscus indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Portland. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Portland is an average the actual date of last frost changes from year to year. Since half of the time in Portland you get surprised by a frost after February 15 be ready to protect your tropical hibiscus 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.