Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Havre you will be able to figure out when to plant larkspur.

Planting Calendar for Larkspur

Frost tolerance for larkspur:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant larkspur quite a bit earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

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

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Havre. You should expect an average low temperature of -30°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 Havre and it is different every year. Since half of the time in Havre you get a frost after May 15 be ready to cover your larkspur in the event of one of those late frosts.

USDA Zone Info for Havre

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Havre

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