Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant calliopsis in Riverton should be figured out by reviewing the USDA zone info.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost.

Since calliopsis are not cold tolerant you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant calliopsis in Riverton is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant calliopsis and expect a good harvest is probably August. If you wait any later than that and your calliopsis may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your calliopsis indoors.

Last Frost Date

The average date of last frost is May 15 in Riverton. 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 Riverton is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Riverton you get surprised by a frost after May 15 be ready to protect your calliopsis if you have a 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.