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

The USDA zone info for Moscow should be reviewed to figure out when to plant periwinkles.

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 you have to wait until after the last frost before you can plant them.

The earliest that you can plant periwinkles in Moscow 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 periwinkles and expect a good harvest is probably August. Any later than that and your periwinkles may not have a chance to fully mature. You can get started a little bit earlier by starting your periwinkles indoors.

Last Frost Date

On average the last frost is on April 15 in Moscow. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Moscow is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Moscow you get surprised by a frost after April 15 so make sure that you are prepared to cover your periwinkles if you have one of those late frosts.

USDA Zone Info for Moscow

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Moscow

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