Before planting it is a good idea to find your USDA Zone info to determine your garden 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 pampas grass in Portland should be determined by using the USDA zone info.

Planting Calendar for Pampas Grass

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

You can not plant pampas grass until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant pampas grass in Portland 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 pampas grass and expect a good harvest is probably August. You probably don't want to wait any later than that or else your pampas grass may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your pampas grass indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Portland and it will vary from year to year. Half of the time in Portland you get a frost after April 15 so always be ready to cover your pampas grass in the event of a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Portland

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