When can I plant Bougainvillea in Zone 4b

One of the first steps we take when we are determining our gardening schedule is find our USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for our area.

The USDA zone info for Zone 4b can be reffered to in order to estimate when it's the best time to plant bougainvillea.


Planting Calendar for Bougainvillea

Frost tolerance for bougainvillea: Not tolerant of frost.
When you should plant them: After the last frost.

You can not plant bougainvillea until after the last frost because they require warm weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant bougainvillea
Possibly ok, but a risky time to plant bougainvillea
Probably not a good time to plant bougainvillea

The earliest that you can plant bougainvillea in Zone 4b 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. If you are starting your bougainvillea indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on May 15 in Zone 4b. We should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Zone 4b is not always accurate our actual date of last frost can change quite a bit from year to year. Half of the time in Zone 4b last frost occurs after May 15 so be sure to be ready to protect your bougainvillea in the event of a late frost.

USDA Zone Info for Zone 4b

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 Zone 4b

You may be interested in our other planting guides for Zone 4b.