Native Plants

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Wednesday - March 17, 2010

From: Little Chute, WI
Region: Midwest
Topic: Shrubs
Title: Native trees or shrubs for containers on roof in Wisconsin
Answered by: Nan Hampton

QUESTION:

Looking for native trees/shrubs to be planted in containers on a flat roof w/south-southeast exposure. Gets pretty warm in the summer and pretty cold in the winter. How big would the container have to be?

ANSWER:

First, let me refer you to our article, Container Gardening with Native Plants. You will see in the article that the recommendation for the size of the pot is:

"Select a container that will accommodate the full sizes of the plants it will house. It should provide ample root space and have a substantial base to offset top-heaviness (both visually and in terms of stability)."

Winter weather in Wisconsin, however, presents an addtional consideration for the size of the pot you can use. I believe you can handle the summer heat as long as you pick plants that are happy growing in full sun and you give them adequate water. However, the winters are another matter. Roots in a container will not have the same protection from freezing that roots buried in the ground will have. With container plants you will need to move them to a protected environment to protect their roots as the winter temperatures drop well below freezing. Consequently, you will need to select plants that fit into containers that you will be able to move to a protected place. You can read advice on preparing container plants for winter weather in the article, Maintaining Winter Gardens in Gladwin, MI, from the National Gardening Association.

Below are shrubs that are Wisconsin natives that grow in full sun. If the your area is in shade (less than 2 hours sun per day) or part shade (2 to 6 hours of sun per day), you can find recommendations for other plants in our Wisconsin Recommended list. You can use the NARROW YOUR SEARCH option to limit the list to only 'Shrubs' by choosing that selection under GENERAL APPEARANCE.

Actaea rubra (red baneberry)

Amorpha fruticosa (desert false indigo)

Cornus racemosa (gray dogwood)

Dasiphora fruticosa ssp. floribunda (shrubby cinquefoil)

Physocarpus opulifolius (common ninebark)

Symphoricarpos albus (common snowberry)

Shepherdia canadensis (russet buffaloberry)

Yucca filamentosa (Adam's needle) and here is more information.

Here are photos of the above plants from our Image Gallery: