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When to Plant Garden Mums in Rock Springs, WY

One of the first steps you take when you are determining 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.

One way of estimating when it's the best time to plant garden mums is to examine the USDA zone info for Rock Springs.


Planting Calendar for Garden Mums

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

Garden Mums are moderately cold tolerant which means that you can start planting them earlier than plants that are more sensitive to the cold.

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

The earliest that you can plant garden mums in Rock Springs is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant garden mums and expect a good harvest is probably September. If you wait any later than that and your garden mums may not have a chance to really do well. Starting your garden mums indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Rock Springs the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Rock Springs and it can change quite a bit from year to year. Half of the time in Rock Springs you get surprised by a frost after April 15 so make sure that you are prepared to protect your garden mums if you have one of those late frosts.

USDA Zone Info for Rock Springs

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 Rock Springs

You may be interested in your other planting guides for Rock Springs.