The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 Rock Springs you will be able to estimate when you can plant evolvulus.

Planting Calendar for Evolvulus

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

Since evolvulus do not do well in cold weather you really should wait until after the last frost before you can plant them.

The earliest that you can plant evolvulus in Rock Springs 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 evolvulus and expect a good harvest is probably August. Any later than that and your evolvulus may not have a chance to grow to maturity. If you are starting your evolvulus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Rock Springs. You should expect an average low temperature of -20°F in the coldest months of winter.

Keep in mind 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 Rock Springs and it is different every year. Half of the time in Rock Springs you get surprised by a frost after April 15 so just be sure to be ready to cover your evolvulus if you have a surprise late frost.

USDA Zone Info for Rock Springs

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Rock Springs

You may be interested in your other planting guides for Rock Springs.