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.

In Waterloo you can figure out when you can plant purple coneflower by referring to 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.

Since purple coneflower are barely cold tolerant you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant purple coneflower in Waterloo 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 grow to maturity. You can get started a couple of weeks earlier by starting your purple coneflower indoors.

Last Frost Date

On average the last frost is on April 15 in Waterloo. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind that USDA zone info for Waterloo is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Waterloo you get surprised by a frost after April 15 so be sure to be ready to cover your purple coneflower if you have a late frost.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Waterloo

You may be interested in your other planting guides for Waterloo.