The USDA Zone info is a great tool for gardeners to help us figure out 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 way of determining when you can plant penstemon is to check out the USDA zone info for Waterville.

Planting Calendar for Penstemon

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

You can plant penstemon a little earlier in the year because they do well in moderate cold.

The earliest that you can plant penstemon in Waterville 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 couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Waterville. It might get as low as -20°F during the coldest months of winter.

Always keep in mind that USDA zone info for Waterville is just an average and the actual date of last frost changes from year to year. Half of the time in Waterville it frosts late in the year after April 15 so be sure to be ready to protect your penstemon if you have one of those late frosts.

USDA Zone Info for Waterville

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Waterville

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