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.

In Superior you can figure out when you can plant pennyroyal by reviewing the USDA zone info.

Planting Calendar for Pennyroyal

Frost tolerance for pennyroyal:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Pennyroyal do well in cold which tells us that you can plant them a quite a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant pennyroyal in Superior 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 pennyroyal and expect a good harvest is probably August. Any later than that and your pennyroyal may not have a chance to really do well. Starting your pennyroyal indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Superior. It might get as low as -25°F during the coldest months of winter.

Always keep in mind that USDA zone info for Superior is an average and the actual date of last frost will vary from year to year. Since half of the time in Superior it frosts late in the year after May 15 be ready to protect your pennyroyal in the event of a late frost.

USDA Zone Info for Superior

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 Superior

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