One of the first steps you take when you are estimating 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.

By using the USDA zone info for Westminster it's possible to estimate 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 has passed.

Periwinkles do not do well in cold weather which means that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant periwinkles in Westminster is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant periwinkles and expect a good harvest is probably September. If you wait 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

In Westminster the average date of last frost happens on January 31. In the coldest months of winter you should expect an average low temperature of 35°F.

Since the USDA zone info for Westminster is not always accurate the actual date of last frost changes from year to year. Half of the time in Westminster you get a frost after January 31 so make sure that you are prepared to cover your periwinkles if you have a late frost.

USDA Zone Info for Westminster

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°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 40°F.

Plants to Grow in Westminster

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