Hoosier Gardener: Aggressive cattails challenge to control

A few people have written lately asking how to get rid of cattails in the wet areas of their landscapes, including reader J.P., who says they are spreading into the tree line.

Of the three species of cattails (Typha spp.) in North America, two are native: the wide-leaf (T. latifolia) and the southern (T. domingensis). Narrow-leaf cattail (T. angustifolia) is not native, but the National Park Service says it is not considered invasive. An invasive plant is frequently defined as one that is not native and has the potential to cause environmental or economic harm to humans, animals or other plants. No one would dispute that cattails can be aggressive, though.

As part of its Great Lakes Research at the Indiana Dunes National Lakeshore, the park service has been monitoring a hybrid (or cross) of at least two of the three cattails to develop T. x glauca, which is considered invasive.

In the residential landscape, there are few options to control cattails, no matter which ones have rooted.

Cattails have vigorous, tenacious roots, which can be dug. But it’s a lot of work, said Ellen Jacquart, an invasive plant expert who retired recently from The Nature Conservancy in Indiana.

Keeping the cattails chopped back to below the soil or water line will eventually weaken the plants, but it may take several years. 

There are chemicals that control cattails, but most are not registered for use by homeowners. We always want to exercise extreme caution when using lawn and garden chemicals around water. Jacquart recommended homeowners and others refer to Purdue University’s list (bit.ly/2wT7cnz) of invasive plant removal contractors.

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Select tight-budded mums

Everyone is ready to plant fall mums in their pots or garden beds. Remember to buy plants where the flower buds have just started to show color. Mums at that stage will last much longer than plants with the flowers open. The same advice goes for potted asters, also available this time of year.

Other items to consider for a fall theme: annual red fountain grass; million bells (Calibrachoa); petunias; Diascia; Nemesia; dusty miller; snapdragons (Antirrhinum majus); Osteospermum; salvia (S. farinacea); pansies or violas; ornamental cabbage or kale; ornamental peppers; Swiss chard; lettuces, especially bronze-leaf types; corn stalks; squash, gourds and pumpkins. Also, snip a few dried seed heads from the garden for another element.

Jo Ellen Meyers Sharp (hoosiergardener.com) is vice president of Garden Writers Association and co-author of “The Indiana Gardener's Guide.” Write to her at P.O. Box 20310, Indianapolis, IN 46220-0310, or email thehoosiergardener@gmail.com.