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.

One way of determining when to plant astilbe is to use the USDA zone info for Waseca.

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.

Since astilbe do ok in moderate cold you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant astilbe in Waseca is April. However, you really should wait until May 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. If you are starting your astilbe indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Waseca. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Waseca is just an average the actual date of last frost changes from year to year. Since half of the time in Waseca you get a frost after May 15 be ready to protect your astilbe if you have a late frost.

USDA Zone Info for Waseca

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 Waseca

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