The USDA Zone info is a great tool for gardeners to help us estimate 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.

The first opportunity to plant penstemon in Honolulu can be determined 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.

Since penstemon do well in moderate cold you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

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

The last month that you can plant penstemon and expect a good harvest is probably November. Any later than that and your penstemon may not have a chance to fully mature. 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

In Honolulu it never frosts. You can expect an average low temperature of 50°F in the coldest months of winter.

Since the USDA zone info for Honolulu is an average the actual date of last frost changes from year to year. Since it never frosts in Honolulu you do not have to be ready to protect your penstemon if you have one of those late frosts.

USDA Zone Info for Honolulu

Here is the info for USDA Zone 12a.

Average Date of Last Frost (spring)	Never
Average Date of First Frost (fall)	Never
Lowest Expected Low	50°F
Highest Expected Low	55°F

This means that on a really cold year, the coldest it will get is 50°F. On most years you should be prepared to experience lows near 55°F.

Plants to Grow in Honolulu

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