Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Boulder City you can estimate when it's possible to plant columbine by using the USDA zone info.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Columbine tend to make it in moderate cold which means that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant columbine in Boulder City is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant columbine and expect a good harvest is probably October. If you wait any later than that and your columbine may not have a chance to fully mature. Starting your columbine indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Boulder City. In the coldest months of winter you should expect an average low temperature of 25°F.

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 Boulder City and it will vary from year to year. Since half of the time in Boulder City it frosts late in the year after February 15 be ready to cover your columbine if you have a surprise late frost.

USDA Zone Info for Boulder City

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Boulder City

You may be interested in your other planting guides for Boulder City.