One of the best tools that you have as gardeners to help us determine 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.

In Helena you can determine when it's a good idea to plant garden mums by checking out the USDA zone info.

Planting Calendar for Garden Mums

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

Since garden mums are one of those plants that can tolerate a little bit of cold weather you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant garden mums in Helena 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 garden mums and expect a good harvest is probably August. Any later than that and your garden mums may not have a chance to really do well. You can get started a few weeks earlier by starting your garden mums indoors.

Last Frost Date

The average date of last frost is May 15 in Helena. It might get as low as -25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Helena and it is different every year. Half of the time in Helena it frosts late in the year after May 15 so always be ready to cover your garden mums if you have a late frost.

USDA Zone Info for Helena

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 Helena

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