Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to determine when to plant periwinkles by reviewing the USDA zone info for Monmouth.

Planting Calendar for Periwinkles

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

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

The earliest that you can plant periwinkles in Monmouth 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. If you wait any later than that and your periwinkles may not have a chance to fully mature. If you are starting your periwinkles indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Monmouth. In the coldest months of winter you can expect an average low temperature of -15°F.

Just be sure to remember that USDA zone info for Monmouth is an average and the actual date of last frost changes from year to year. Since half of the time in Monmouth there is a last frost after April 15 be ready to cover your periwinkles if you have a surprise late frost.

USDA Zone Info for Monmouth

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 Monmouth

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