Before planting it is a good idea to find your USDA Zone info to determine 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.

You will be able to estimate when it's the best time to plant penstemon by referring to the USDA zone info for South Milwaukee.

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 bit earlier in the year because they do well in moderate cold.

The earliest that you can plant penstemon in South Milwaukee 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 little bit earlier.

Last Frost Date

In South Milwaukee the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Remember that USDA zone info for South Milwaukee is just an average and the actual date of last frost will vary from year to year. Since half of the time in South Milwaukee you get a frost after April 15 be ready to protect your penstemon if you have a surprise late frost.

USDA Zone Info for South Milwaukee

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 South Milwaukee

You may be interested in your other planting guides for South Milwaukee.