One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when to plant astilbe is to consult the USDA zone info for Cynthiana.

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 means that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant astilbe in Cynthiana 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. Starting your astilbe indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Cynthiana. It might get as low as -5°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Cynthiana and it is different every year. Since half of the time in Cynthiana you get surprised by a frost after April 15 be ready to protect your astilbe in the event of a late frost.

USDA Zone Info for Cynthiana

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 Cynthiana

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