The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can estimate when to plant purple coneflower in River Rouge by reviewing the USDA zone info.

Planting Calendar for Purple Coneflower

Frost tolerance for purple coneflower:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Purple Coneflower are barely cold tolerant which means that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant purple coneflower in River Rouge 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 purple coneflower and expect a good harvest is probably August. If you wait any later than that and your purple coneflower may not have a chance to really do well. If you are starting your purple coneflower indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in River Rouge. In the coldest months of winter you should expect an average low temperature of -5°F.

Keep in mind that USDA zone info for River Rouge is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in River Rouge you get a frost after April 15 so make sure that you are prepared to cover your purple coneflower in the event of a late frost.

USDA Zone Info for River Rouge

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 River Rouge

You may be interested in your other planting guides for River Rouge.