One of the first steps you take when you are figuring out your gardening schedule is find your 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.

One way of figuring out when it's possible to plant hypericum is to consult the USDA zone info for Holmen.

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.

You can plant hypericum slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant hypericum in Holmen 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. You probably don't want to wait any later than that or else your hypericum may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your hypericum indoors.

Last Frost Date

The average date of last frost is May 15 in Holmen. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Holmen may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Holmen it frosts late in the year after May 15 so always be ready to cover your hypericum if you have a late frost.

USDA Zone Info for Holmen

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 Holmen

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