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 San Antonio you can figure out when you can plant penstemon by reviewing 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.

Penstemon are one of those plants that can tolerate a little bit of cold weather which means that you can plant them a little bit earlier than other plants that might not handle the cold.

The earliest that you can plant penstemon in San Antonio is February. However, you really should wait until March if you don't want to take any chances.

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

Last Frost Date

The average date of last frost is March 15 in San Antonio. You should expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for San Antonio is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in San Antonio you get a frost after March 15 so just be sure to be ready to protect your penstemon in the event of a surprise late frost.

USDA Zone Info for San Antonio

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

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

Plants to Grow in San Antonio

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