One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In San Bernardino you can estimate when you can plant penstemon by referring to the USDA zone info.

Planting Calendar for Penstemon

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

Since penstemon do well in moderate cold you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant penstemon in San Bernardino 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 penstemon and expect a good harvest is probably October. If you wait any later than that and your penstemon may not have a chance to grow to maturity. If you are starting your penstemon indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In San Bernardino the average date of last frost happens on February 15. You should expect an average low temperature of 25°F in the coldest months of winter.

Keep in mind that USDA zone info for San Bernardino is just an average and the actual date of last frost changes from year to year. Half of the time in San Bernardino last frost occurs after February 15 so make sure that you are prepared to cover your penstemon if you have a late frost.

USDA Zone Info for San Bernardino

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 San Bernardino

You may be interested in your other planting guides for San Bernardino.