One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Huntsville you can figure out when you can plant penstemon by using 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 do well in some cold which tells us that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Huntsville 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. Any later than that and your penstemon may not have a chance to really do well. Starting your penstemon indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Huntsville the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Huntsville and it will vary from year to year. Half of the time in Huntsville last frost occurs after March 15 so make sure that you are prepared to cover your penstemon in the event of one of those late frosts.

USDA Zone Info for Huntsville

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 Huntsville

You may be interested in your other planting guides for Huntsville.