When to Plant Astilbe in Zone 5b

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Zone 5b you should be able to figure out when it's the best time to plant astilbe.

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Planting Calendar for Astilbe

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

Astilbe are barely cold tolerant which tells us that you can plant them slightly earlier than more sensitive plants.

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

The earliest that you can plant astilbe in Zone 5b 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 astilbe and expect a good harvest is probably August. If you wait any later than that and your astilbe may not have a chance to fully mature. You can get started a few weeks earlier by starting your astilbe indoors.

Last Frost Date

The average date of last frost is April 15 in Zone 5b. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Zone 5b is not always accurate the actual date of last frost is different every year. Half of the time in Zone 5b last frost occurs after April 15 so be sure to be ready to protect your astilbe if you have a late frost.

USDA Zone Info for Zone 5b

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 Zone 5b

You may be interested in your other planting guides for Zone 5b.