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When to Plant Ornamental Grasses in Washington, IA

One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By looking at the USDA zone info for Washington you should be able to determine when to plant ornamental grasses.

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Planting Calendar for Ornamental Grasses

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

Since ornamental grasses are barely cold tolerant you can plant them a bit earlier in the year than other plants that might not handle the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant ornamental grasses
Possibly ok, but a risky time to plant ornamental grasses
Probably not a good time to plant ornamental grasses

The earliest that you can plant ornamental grasses in Washington 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 ornamental grasses and expect a good harvest is probably August. If you wait any later than that and your ornamental grasses may not have a chance to fully mature. Starting your ornamental grasses indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Washington. In the coldest months of winter you can 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 Washington and it will vary from year to year. Half of the time in Washington there is a last frost after April 15 so be sure to be ready to protect your ornamental grasses in the event of one of those late frosts.

USDA Zone Info for Washington

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 Washington

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