Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Helena should be reviewed to figure out when it's a good idea to plant cleome.

Planting Calendar for Cleome

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

Cleome require warm weather which means that you really should wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant cleome 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 cleome and expect a good harvest is probably August. You probably don't want to wait any later than that or else your cleome may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your cleome indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Helena. You should expect an average low temperature of 10°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Helena and it changes from year to year. Half of the time in Helena you get surprised by a frost after March 15 so always be ready to cover your cleome if you have one of those late frosts.

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.