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.

It's possible to estimate when to plant penstemon by checking out the USDA zone info for Cape Girardeau.

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 moderately cold tolerant you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant penstemon in Cape Girardeau 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. If you are starting your penstemon indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Cape Girardeau. You should expect an average low temperature of -5°F in the coldest months of winter.

Always keep in mind that USDA zone info for Cape Girardeau is an average and the actual date of last frost will vary from year to year. Since half of the time in Cape Girardeau you get surprised by a frost after April 15 be ready to cover your penstemon if you have a late frost.

USDA Zone Info for Cape Girardeau

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°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 0°F.

Plants to Grow in Cape Girardeau

You may be interested in your other planting guides for Cape Girardeau.