One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Riverton should be looked at to figure out when it's possible to plant argyranthemum.

Planting Calendar for Argyranthemum

Frost tolerance for argyranthemum:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since argyranthemum require warm weather you need to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant argyranthemum 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 argyranthemum and expect a good harvest is probably August. If you wait any later than that and your argyranthemum may not have a chance to grow to maturity. Starting your argyranthemum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Riverton. It might get as low as -25°F during the coldest months of winter.

It's important to remember that USDA zone info for Riverton is just an average and the actual date of last frost is different every year. Since half of the time in Riverton there is a last frost after May 15 be ready to cover your argyranthemum 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.