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.

A way of making a decision about when it's a good idea to plant bougainvillea is to consult the USDA zone info for Lewiston.

Planting Calendar for Bougainvillea

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

Bougainvillea require warm weather which means that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant bougainvillea in Lewiston is April. However, you really should wait until May 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 fully mature. 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

In Lewiston the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that USDA zone info for Lewiston is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Lewiston it frosts late in the year after April 15 be ready to protect your bougainvillea if you have a surprise late frost.

USDA Zone Info for Lewiston

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Lewiston

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