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.

The USDA zone info for Helena can be used to figure out when to plant lavender.

Planting Calendar for Lavender

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

Lavender are moderately cold tolerant which tells us that you can get them planted earlier than other frost tender plants.

The earliest that you can plant lavender 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 lavender and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lavender may not have a chance to really do well. You can get started a couple of weeks earlier by starting your lavender indoors.

Last Frost Date

On average the last frost is on May 15 in Helena. In the coldest months of winter you should expect an average low temperature of -25°F.

Just be sure to remember that USDA zone info for Helena is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Helena you get a frost after May 15 be ready to protect your lavender in the event of a surprise 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.