Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant penstemon in Vernal should be estimated by referring to 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.

Penstemon can survive in mild cold which means 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 Vernal 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 fully mature. Starting your penstemon indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Vernal the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Vernal is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Vernal there is a last frost after April 15 be ready to cover your penstemon if you have one of those late frosts.

USDA Zone Info for Vernal

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 Vernal

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