The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of determining when it's a good idea to plant penstemon is to use the USDA zone info for Cary.

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 just a bit earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Cary 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 grow to maturity. 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 April 15 in Cary. In the coldest months of winter you can expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Cary may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Cary you get surprised by a frost after April 15 so make sure that you are prepared to cover your penstemon in the event of a late frost.

USDA Zone Info for Cary

Here is the info for USDA Zone 5b.

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

Plants to Grow in Cary

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