One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant bougainvillea in Havre can be determined by looking at the USDA zone info.

Planting Calendar for Bougainvillea

Frost tolerance for bougainvillea:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's not a good idea to plant bougainvillea until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant bougainvillea 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 bougainvillea and expect a good harvest is probably August. If you wait any later than that and your bougainvillea may not have a chance to grow to maturity. If you are starting your bougainvillea indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Havre. In the coldest months of winter you can expect an average low temperature of -30°F.

Remember that the actual date of last frost is just 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 be sure to be ready to protect your bougainvillea in the event of a surprise 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.