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 it's a good idea to plant astilbe is to refer to the USDA zone info for Highland Park.

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 means that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant astilbe in Highland Park 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 really do well. If you are starting your astilbe indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Highland Park the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Highland Park is an average the actual date of last frost will vary from year to year. Half of the time in Highland Park you get surprised by a frost after April 15 so just be sure to be ready to protect your astilbe in the event of a late frost.

USDA Zone Info for Highland Park

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 Highland Park

You may be interested in your other planting guides for Highland Park.