When to Plant Gladiolus in Riverton, WY

One of the first steps you take when you are estimating your gardening schedule is find your 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.

A common way of estimating when to plant gladiolus is to consult the USDA zone info for Riverton.


Planting Calendar for Gladiolus

Frost tolerance for gladiolus: Tolerant of a very small amount of frost.
When to plant: Up to 3 weeks before last frost.

Gladiolus are barely cold tolerant which tells us that you can plant them slightly earlier than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant gladiolus
Possibly ok, but a risky time to plant gladiolus
Probably not a good time to plant gladiolus

The earliest that you can plant gladiolus in Riverton 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 gladiolus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your gladiolus may not have a chance to really do well. If you are starting your gladiolus indoors then you might be able to get away with starting them a couple of weeks earlier.

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.

It's important to remember that USDA zone info for Riverton is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Riverton there is a last frost after May 15 be ready to cover your gladiolus 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.