One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of making a decision about when to plant hibiscus is to consult the USDA zone info for Havre.

Planting Calendar for Hibiscus

Frost tolerance for hibiscus:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's a bad idea to plant hibiscus until after the last frost because they are not cold tolerant.

The earliest that you can plant hibiscus in Havre is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant hibiscus and expect a good harvest is probably August. Any later than that and your hibiscus may not have a chance to fully mature. If you are starting your hibiscus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Havre the average date of last frost happens on May 15. 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 changes from year to year. Half of the time in Havre there is a last frost after May 15 so just be sure to be ready to cover your hibiscus in the event of a late frost.

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.