One of the best tools that you have as gardeners to help us estimate your 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 your area.

You will be able to figure out when it's possible to plant hypericum by using the USDA zone info for Princeton.

Planting Calendar for Hypericum

Frost tolerance for hypericum:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Hypericum are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant hypericum in Princeton is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant hypericum and expect a good harvest is probably August. If you wait any later than that and your hypericum may not have a chance to grow to maturity. Starting your hypericum indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Princeton. You should expect an average low temperature of -30°F in the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Princeton and it will vary from year to year. Since half of the time in Princeton last frost occurs after May 15 be ready to cover your hypericum if you have one of those late frosts.

USDA Zone Info for Princeton

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Princeton

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