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 Molalla you can estimate when it's a good idea to plant periwinkles 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 has passed.

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

The earliest that you can plant periwinkles in Molalla 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. Starting your periwinkles indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Molalla the average date of last frost happens on March 15. It might get as low as 15°F during the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Molalla and it changes from year to year. Since half of the time in Molalla it frosts late in the year after March 15 be ready to cover your periwinkles if you have a surprise late frost.

USDA Zone Info for Molalla

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Molalla

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