Before planting it is a good idea to find your USDA Zone info to determine 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.

The USDA zone info for Boulder City should be reviewed to figure out when it's the best time to plant salpiglossis.

Planting Calendar for Salpiglossis

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

You really shouldn't plant salpiglossis until after all chance of frost has passed because they require warm weather.

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

The last month that you can plant salpiglossis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your salpiglossis may not have a chance to fully mature. If you are starting your salpiglossis indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost is on February 15 in Boulder City. It might get as low as 25°F during the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Boulder City and it can change quite a bit from year to year. Half of the time in Boulder City last frost occurs after February 15 so make sure that you are prepared to cover your salpiglossis in the event of 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.