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

A way of determining when it's possible to plant campanula is to refer to the USDA zone info for Riverton.

Planting Calendar for Campanula

Frost tolerance for campanula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant campanula just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant campanula in Riverton 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 campanula and expect a good harvest is probably August. If you wait any later than that and your campanula may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your campanula indoors.

Last Frost Date

On average the last frost is on May 15 in Riverton. In the coldest months of winter you can expect an average low temperature of -25°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Riverton and it can change quite a bit from year to year. Since half of the time in Riverton you get a frost after May 15 be ready to cover your campanula in the event of a surprise late frost.

USDA Zone Info for Riverton

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 Riverton

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