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

You should be able to figure out when it's possible to plant astilbe by checking out the USDA zone info for Oskaloosa.

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 very little cold which tells us that 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 Oskaloosa 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 grow to maturity. You can get started a little bit earlier by starting your astilbe indoors.

Last Frost Date

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

Always keep in mind that USDA zone info for Oskaloosa may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Oskaloosa last frost occurs after April 15 so be sure to be ready to cover your astilbe in the event of a surprise late frost.

USDA Zone Info for Oskaloosa

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 Oskaloosa

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