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.

The first chance to plant pampas grass in Zone 4b should be figured out 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.

It's a bad idea to plant pampas grass until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant pampas grass in Zone 4b is May. However, you really should wait until June 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. If you wait 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 little bit earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Zone 4b. It might get as low as -25°F during the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Zone 4b and it can change quite a bit from year to year. Since half of the time in Zone 4b there is a last frost after May 15 be ready to cover your pampas grass if you have one of those late frosts.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.