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 Duluth you can determine when you can plant hardy hibiscus by using the USDA zone info.

Planting Calendar for Hardy Hibiscus

Frost tolerance for hardy hibiscus:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant hardy hibiscus quite a bit earlier in the year because they are very cold tolerant.

The earliest that you can plant hardy hibiscus in Duluth 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 hardy hibiscus and expect a good harvest is probably August. Any later than that and your hardy hibiscus may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your hardy hibiscus indoors.

Last Frost Date

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

Just be sure to remember that USDA zone info for Duluth is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Duluth you get surprised by a frost after May 15 be ready to protect your hardy hibiscus if you have one of those late frosts.

USDA Zone Info for Duluth

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 Duluth

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