When can I plant Pennyroyal in Zone 4b

One of the best tools that we have as gardeners to help us figure out our gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for our area.

The USDA zone info for Zone 4b can be looked at to figure out when to plant pennyroyal.


Planting Calendar for Pennyroyal

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

Since pennyroyal are one of those plants that can tolerate quite a bit of cold weather you can plant them much earlier in the year than other plants that might not handle the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant pennyroyal
Possibly ok, but a risky time to plant pennyroyal
Probably not a good time to plant pennyroyal

The earliest that you can plant pennyroyal in Zone 4b 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. If you wait any later than that and your pennyroyal may not have a chance to fully mature. 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 when the weather gets warmer is on May 15 in Zone 4b. In the coldest months of winter we can expect an average low temperature of -25°F.

It's important to remember that our actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 4b and it will vary from year to year. Half of the time in Zone 4b there is a last frost after May 15 so just be sure to be ready to protect your pennyroyal in the event of one of those late frosts.

USDA Zone Info for Zone 4b

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 Zone 4b

You may be interested in our other planting guides for Zone 4b.