One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. 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 Hilton Head Island.

Planting Calendar for Penstemon

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

Penstemon tend to make it in some cold which means that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Hilton Head Island 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. You probably don't want to wait any later than that or else your penstemon may not have a chance to grow to maturity. If you are starting your penstemon indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on March 15 in Hilton Head Island. In the coldest months of winter you should expect an average low temperature of 15°F.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Hilton Head Island and it is different every year. Half of the time in Hilton Head Island you get surprised by a frost after March 15 so be sure to be ready to cover your penstemon if you have one of those late frosts.

USDA Zone Info for Hilton Head Island

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 Hilton Head Island

You may be interested in your other planting guides for Hilton Head Island.