One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Zone 4b can be looked at to figure out when you can plant purple coneflower.

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.

You can plant purple coneflower just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant purple coneflower in Zone 4b is April. However, you really should wait until May 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. Any later than that and your purple coneflower may not have a chance to really do well. You can get started a couple of weeks earlier by starting your purple coneflower indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Zone 4b. In the coldest months of winter you can expect an average low temperature of -25°F.

Just be sure to remember that USDA zone info for Zone 4b is just an average and the actual date of last frost will vary from year to year. Since half of the time in Zone 4b it frosts late in the year after May 15 be ready to protect your purple coneflower in the event of a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.