One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Chisholm you can estimate when it's a good idea to plant periwinkles by referring to 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 necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Chisholm 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 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 May 15 in Chisholm. It might get as low as -35°F during the coldest months of winter.

Remember that USDA zone info for Chisholm is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Chisholm last frost occurs after May 15 be ready to cover your periwinkles if you have a surprise late frost.

USDA Zone Info for Chisholm

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Chisholm

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