The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of making a decision about when it's a good idea to plant periwinkles is to use the USDA zone info for Glendale.

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 the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant periwinkles in Glendale 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 really do well. 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 January 31 in Glendale. You should expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for Glendale is an average the actual date of last frost is different every year. Half of the time in Glendale 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 Glendale

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

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

Plants to Grow in Glendale

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