The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Helena can be reviewed to figure out when to plant scaevola.

Planting Calendar for Scaevola

Frost tolerance for scaevola:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Scaevola require warm weather which means that it's important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant scaevola 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 scaevola and expect a good harvest is probably August. If you wait any later than that and your scaevola may not have a chance to grow to maturity. You can get started a little bit earlier by starting your scaevola indoors.

Last Frost Date

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

Since the USDA zone info for Helena is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Helena you get a frost after March 15 so make sure that you are ready to cover your scaevola 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.