Before planting it is a good idea to find your USDA Zone info to estimate 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 Highland you can estimate when it's possible to plant pennyroyal by checking out 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 tend to make it in a bit of cold which tells us that you can plant them a lot earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant pennyroyal in Highland 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 pennyroyal and expect a good harvest is probably September. Any later than that and your pennyroyal may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your pennyroyal indoors.

Last Frost Date

In Highland the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Highland is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Highland last frost occurs after April 15 so just be sure to be ready to cover your pennyroyal in the event of a surprise late frost.

USDA Zone Info for Highland

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 Highland

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