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.

You can determine when to plant periwinkles in Boulder City by using the USDA zone info.

Planting Calendar for Periwinkles

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

Since periwinkles are not cold tolerant it is important to wait until after the last frost before you can plant them.

The earliest that you can plant periwinkles in Boulder City is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant periwinkles and expect a good harvest is probably September. You probably don't want to wait any later than that or else your periwinkles may not have a chance to really do well. If you are starting your periwinkles indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Boulder City. In the coldest months of winter you should expect an average low temperature of 25°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Boulder City and it can change quite a bit from year to year. Since half of the time in Boulder City last frost occurs after February 15 be ready to cover your periwinkles if you have one of those late frosts.

USDA Zone Info for Boulder City

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Boulder City

You may be interested in your other planting guides for Boulder City.