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.

A way of making a decision about when it's possible to plant chrysanthemums is to use the USDA zone info for Helena.

Planting Calendar for Chrysanthemums

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

Since chrysanthemums are barely cold tolerant you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant chrysanthemums 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 chrysanthemums and expect a good harvest is probably August. If you wait any later than that and your chrysanthemums may not have a chance to grow to maturity. If you are starting your chrysanthemums indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Helena. It might get as low as 10°F during the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Helena and it will vary from year to year. Half of the time in Helena you get surprised by a frost after March 15 so make sure that you are prepared to cover your chrysanthemums in the event of a late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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