The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Billings you can figure out when it's possible to plant bougainvillea by referring to 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.

Since bougainvillea do not do well in cold weather it's important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant bougainvillea in Billings 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. Any later than that and your bougainvillea may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your bougainvillea indoors.

Last Frost Date

The average date of last frost is May 15 in Billings. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Billings is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Billings there is a last frost after May 15 be ready to cover your bougainvillea if you have one of those late frosts.

USDA Zone Info for Billings

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 Billings

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