One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to estimate when it's a good idea to plant penstemon by looking at the USDA zone info for Oconomowoc.

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 just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant penstemon in Oconomowoc 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 grow to maturity. Starting your penstemon indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Oconomowoc. You can expect an average low temperature of -20°F in the coldest months of winter.

Always keep in mind that USDA zone info for Oconomowoc is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Oconomowoc you get surprised by a frost after April 15 be ready to cover your penstemon if you have a surprise late frost.

USDA Zone Info for Oconomowoc

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 Oconomowoc

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