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

A common way of making a decision about when you can plant penstemon is to examine the USDA zone info for Ashland.

Planting Calendar for Penstemon

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

Penstemon do ok in mild cold which tells us that you can plant them a little earlier in the year than other frost tender plants.

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

The last month that you can plant penstemon and expect a good harvest is probably August. If you wait any later than that and your penstemon may not have a chance to fully mature. You can get started a few weeks earlier by starting your penstemon indoors.

Last Frost Date

The average date of last frost is May 15 in Ashland. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Ashland is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Ashland last frost occurs after May 15 be ready to cover your penstemon if you have a surprise late frost.

USDA Zone Info for Ashland

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Ashland

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