One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Detroit you can estimate when it's possible to plant hypericum by looking at the USDA zone info.

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 do well in a tiny bit of cold which means that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant hypericum in Detroit 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 hypericum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your hypericum may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your hypericum indoors.

Last Frost Date

The average date of last frost is April 15 in Detroit. In the coldest months of winter you can expect an average low temperature of -5°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Detroit and it can change quite a bit from year to year. Half of the time in Detroit you get a frost after April 15 so make sure that you are prepared to protect your hypericum in the event of one of those late frosts.

USDA Zone Info for Detroit

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Detroit

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