Gardening Tips and Highlights Waushara County Master Gardeners

Too much water in a garden can be concerning

Drought is such a common gardening threat that it gets a lot of attention. Far less attention is paid, though, to what happens when too much rain comes down, as it did this summer in much of the country.

Plants that wash away or that rot in soggy soil are the most obvious problems; however, a handful of more subtle, lingering, and long-term problems also can follow excess wetness. Some plants, such as lavender, wormwood or artemisia, lambs ear’s, and carnations and other dianthus have little tolerance for wet soil and can die after just a day or two of sogginess.

Daylilies, many iris, lilyturf and mondo grass may not die, but some of the roots may rot, putting the plant at risk of other setbacks, such as intense heat or cold or future dry spells. The long-term outcome depends on the plant, how long it was sitting in soggy soil, and whether the plant sidesteps setbacks while roots regrow.


An overabundance of moisture leads to widespread spotting, streaking, and disease-related browning of leaves, mostly caused by fungal diseases that thrive in warm, humid or wet conditions. The good news is that plants usually grow through most leaf diseases, they may look bad and or drop leaves prematurely.

Don’t assume a tree or shrub has died if it drops its leaves early this year or if a perennial plant has turned yellow, brown, or wilted back to the ground. Wait until next spring to see if the plants and branches push out new growth. Lawns are usually resilient to flooding, but they can suffer from rust, mildew, and other fungal diseases along with any other plant. Wet lawns often produce assorted mushrooms-like growths; damp, mulched beds may produce blob-like growths called slime mold that start out yellow-orange and turn black.

Slime mold is harmless to pets and people but can be raked off if you don’t like the looks of it. One of the worst post-soggy signs is trees that have started to lean. That’s a sign that the tree is losing root support, possibly from a combination of soggy soil that rotted roots as well as the weight of water and wind on wet leaves. It’s worth trying to salvage them by pushing them back upright and staking them for up to a year.

Heavy rains give good clues on avoiding trouble in the future. Look for depressions where water stood for days and level it out with additional soil. Look where excess, unwanted water flowed, and correct it by adding drain pipes, dry streambeds, or swales to redirect it to a more desirable area. Consider adding a rain garden to capture and drain runoff instead of letting it wash away. For downspouts that blew soil or mulch out into the yard, mitigate the force by adding a bed of stones or a splash block at the bottom.

This information was obtained from