The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when it's a good idea to plant astilbe in Round Lake 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 are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can plant them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant astilbe in Round Lake 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. You can get started a few weeks earlier by starting your astilbe indoors.

Last Frost Date

The average date of last frost is April 15 in Round Lake. It might get as low as -15°F during the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Round Lake and it is different every year. Half of the time in Round Lake you get surprised by a frost after April 15 so make sure that you are ready to cover your astilbe if you have a late frost.

USDA Zone Info for Round Lake

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 Round Lake

You may be interested in your other planting guides for Round Lake.