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.

By checking out the USDA zone info for Keller it's possible to estimate when it's a good idea to plant periwinkles.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's not a good idea to plant periwinkles until after the last frost because they require warm weather.

The earliest that you can plant periwinkles in Keller 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. You probably don't want to wait any later than that or else your periwinkles may not have a chance to grow to maturity. 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

On average all chance of frost has passed is on March 15 in Keller. In the coldest months of winter you should expect an average low temperature of 10°F.

Always keep in mind that USDA zone info for Keller is just an average and the actual date of last frost changes from year to year. Since half of the time in Keller you get surprised by a frost after March 15 be ready to cover your periwinkles if you have a late frost.

USDA Zone Info for Keller

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 Keller

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