One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to determine when it's the best time to plant fountain grass by using the USDA zone info for Mercer Island.

Planting Calendar for Fountain Grass

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

Fountain Grass are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant fountain grass in Mercer Island 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 fountain grass and expect a good harvest is probably August. Any later than that and your fountain grass may not have a chance to fully mature. If you are starting your fountain 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 has passed is on March 15 in Mercer Island. In the coldest months of winter you should expect an average low temperature of 15°F.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Mercer Island and it can change quite a bit from year to year. Half of the time in Mercer Island there is a last frost after March 15 so always be ready to protect your fountain grass if you have a surprise late frost.

USDA Zone Info for Mercer Island

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Mercer Island

You may be interested in your other planting guides for Mercer Island.