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.

You should be able to determine when it's a good idea to plant penstemon by referring to the USDA zone info for Lewisville.

Planting Calendar for Penstemon

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

Penstemon can survive in moderate cold which tells us that you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant penstemon in Lewisville 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 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 April 15 in Lewisville. It might get as low as 5°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Lewisville is just an average and the actual date of last frost changes from year to year. Half of the time in Lewisville it frosts late in the year after April 15 so make sure that you are prepared to protect your penstemon in the event of one of those late frosts.

USDA Zone Info for Lewisville

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Lewisville

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