Before planting it is a good idea to find your USDA Zone info to figure out 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.

You can estimate when you can plant pampas grass in Portland by reviewing 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.

Pampas Grass are not cold tolerant which means that it's important to wait until it warms up after the last frost before you can plant them.

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. Any later than that and your pampas grass may not have a chance to grow to maturity. If you are starting your pampas grass indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Portland. You should expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Portland and it can change quite a bit from year to year. Since half of the time in Portland last frost occurs after April 15 be ready to cover your pampas grass in the event of one of those late frosts.

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.