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

In Plattsmouth you can figure out when it's the best time to plant periwinkles by looking at the USDA zone info.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Periwinkles are not cold tolerant which tells us that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant periwinkles in Plattsmouth 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 grow to maturity. 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 April 15 in Plattsmouth. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Plattsmouth is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Plattsmouth you get surprised by a frost after April 15 be ready to protect your periwinkles in the event of a surprise late frost.

USDA Zone Info for Plattsmouth

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 Plattsmouth

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