One of the best tools that you have as gardeners to help us figure out 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.

By checking out the USDA zone info for Silverton you will be able to determine when it's the best time 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.

It's probably not a good idea to plant periwinkles until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant periwinkles in Silverton 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. You can get started a little bit earlier by starting your periwinkles indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Silverton. It might get as low as 10°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Silverton and it can change quite a bit from year to year. Since half of the time in Silverton you get surprised by a frost after March 15 be ready to protect your periwinkles if you have a late frost.

USDA Zone Info for Silverton

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Silverton

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