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.

One way of figuring out when you can plant chrysanthemum is to check out the USDA zone info for Helena.

Planting Calendar for Chrysanthemum

Frost tolerance for chrysanthemum:	Not tolerant of frost.
When to plant:	After the last frost.

You can not plant chrysanthemum until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant chrysanthemum in Helena 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 chrysanthemum and expect a good harvest is probably August. Any later than that and your chrysanthemum may not have a chance to grow to maturity. If you are starting your chrysanthemum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Helena the average date of last frost happens on March 15. You should expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Helena is not always accurate the actual date of last frost is different every year. Since half of the time in Helena last frost occurs after March 15 be ready to protect your chrysanthemum 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.