One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when it's the best time to plant penstemon is to consult the USDA zone info for Santa Rosa.

Planting Calendar for Penstemon

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

Since penstemon are one of those plants that can tolerate a little bit of cold weather you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant penstemon in Santa Rosa 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 really do well. You can get started a little bit earlier by starting your penstemon indoors.

Last Frost Date

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

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Santa Rosa and it can change quite a bit from year to year. Half of the time in Santa Rosa last frost occurs after February 15 so be sure to be ready to cover your penstemon in the event of a late frost.

USDA Zone Info for Santa Rosa

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 Santa Rosa

You may be interested in your other planting guides for Santa Rosa.