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.

It's possible to estimate when it's a good idea to plant astilbe by using the USDA zone info for Derby.

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 do ok in moderate cold which tells us that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant astilbe in Derby 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. You probably don't want to wait any later than that or else your astilbe may not have a chance to grow to maturity. 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

In Derby the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -5°F.

Just be sure to remember that USDA zone info for Derby may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Derby you get surprised by a frost after April 15 be ready to cover your astilbe in the event of a surprise late frost.

USDA Zone Info for Derby

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 Low	0°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 Derby

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