Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of estimating when it's the best time to plant periwinkles is to examine the USDA zone info for Eldorado.

Planting Calendar for Periwinkles

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

Periwinkles do not do well in cold weather which means that you have to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant periwinkles in Eldorado 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. If you wait any later than that and your periwinkles may not have a chance to really do well. You can get started a couple of weeks earlier by starting your periwinkles indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Eldorado. You should expect an average low temperature of -5°F in 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 Eldorado and it changes from year to year. Since half of the time in Eldorado there is a last frost after April 15 be ready to cover your periwinkles in the event of a late frost.

USDA Zone Info for Eldorado

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Eldorado

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