When to Plant Astilbe in Flat Rock, MI

Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when to plant astilbe by referring to the USDA zone info for Flat Rock.


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 tend to make it in some cold which tells us that you can plant them a bit earlier in the year than other frost tender 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 Flat Rock 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. Any later than that and your astilbe may not have a chance to fully mature. You can get started a little bit earlier by starting your astilbe indoors.

Last Frost Date

In Flat Rock the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Flat Rock may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Flat Rock you get a frost after April 15 so be sure to be ready to protect your astilbe in the event of one of those late frosts.

USDA Zone Info for Flat Rock

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-5°F
Highest Expected Low0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Flat Rock

You may be interested in your other planting guides for Flat Rock.