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

In New Haven you can figure out when it's possible to plant astilbe by looking at the USDA zone info.

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 frost tender plants.

The earliest that you can plant astilbe in New Haven 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 fully mature. Starting your astilbe indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In New Haven the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for New Haven is just an average and the actual date of last frost changes from year to year. Half of the time in New Haven you get surprised by a frost after April 15 so make sure that you are ready to cover your astilbe in the event of a late frost.

USDA Zone Info for New Haven

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in New Haven

You may be interested in your other planting guides for New Haven.