It's been soggy outside, but that's OK with these types of plant life.
While there doesn’t appear to be an ark being built, it sure feels like we need one. Yet some plants are thriving. Let’s look at what can tolerate wet conditions.
As we’ve mentioned before, it’s not so much the plants that tolerate the water, but the quality of soil that allows roots to breathe. The issue becomes which plants can withstand their roots in an oxygen-free environment for any extended period of time.
Some plants thrive in flooded or low-lying areas. While these mosquito breeding grounds may not offer the diversity that upland areas do, they are filled with water-loving or flood-tolerant plants.
Several trees do well, though as a group they aren’t the strongest wooded specimens. Alders (Alnus), birches (Betula), cottonwoods and poplars (Populus), tuliptrees (Liriodendron, sometimes called yellow poplar) and willows (Salix) can tolerate wet soil. Silver maples (Acer saccharinum) are one of the few maples that thrive. Most other hardwood maples tend to up and die.
Surprisingly, pin oaks (Quercus palustris) are a bottomland tree and can withstand flooded conditions. While few people will plant them, pecans also can tolerate wet conditions.
The one caveat is that, while these trees can tolerate wet soils, they don’t develop a deep root system. Most are shallow-rooted, trying to get as much oxygen to the roots as possible, especially as the waters recede. Without an extensive root system, trees don’t last as long.
Softwood trees also have an annoying habit of breaking off in ice, snow and wind storms.
Water-loving perennials are harder to put in definitive categories. By and large, native plants have a stronger tendency to adapt to wet-dry conditions.
Two of the natives that don’t seem to mind are purple coneflowers and black-eyed Susans.
Black-eyed Susans (Rudbeckia) produce daisy-like yellow flowers with a dark center, starting in the next couple of weeks and going through September. Their sandpaper-like leaves make them unappealing to many four-legged creatures.
Unfortunately, the plants aren’t that large, and while their roots can tolerate wet conditions, the plant ends up rotting if it is covered with water.
Purple coneflowers (Echinacea) are a little better because they often can reach 3 to 4 feet high. They also have the advantage of producing stronger stems and more flowers, starting in mid-June and going through September, if the dead flowers are removed regularly. While most native forms are purple to purplish-pink, some recent introductions tend toward white, yellow and orange.
Another native plant that tolerates the end of the gutter is Joe Pye Weed (Eupatorium), which is plagued with “weed” in its name. It’s not invasive, isn’t poisonous if eaten and doesn’t cause most people any skin problems. True, the native form can reach 6 to 8 feet tall, but some cultivars are only half that size. It flowers in August and September, and will attract butterflies.
The natives also have the advantage of tolerating dry conditions … if and when dry conditions show up.
The large-leafed Colocasia and Alocasia, sometimes called Elephant Ears, can be planted in soil that ends up being waterlogged. The same applies to Cannas. In fact, if you have them in a pot, you can sometimes just keep the pot submerged in another pot filled with water.
Finally, you almost can’t go wrong with day lilies (Hemerocallis).
The plants are non-native, though you’d be hard pressed to guess that because they can be found along the back of any county road. They were one of the first plants settlers stuck in the ground as they crossed the prairies centuries ago.
Day lilies do well in just about any soil type, and under any water condition. They prefer full sun but can tolerate shade. Plants have been known to be submerged up to their tips for several weeks and still survive.
Day lilies bloom May through September, depending on the type. While most bloom during the day, some night-flowering day lilies perfume the air with a sweet fragrance, hoping to attract some insect to pollinate their flowers.
The wild forms tend to spread, taking over a yard as quickly as crabgrass. However, most of the newer forms are clump-forming, seldom spreading much.
A few vegetables and fewer fruits tolerate excess rain. Corn will thrive but must have some oxygen around its roots. Excess moisture prevents corn from forming the bracer roots it needs later in the season.
Fruit plants like the moisture but hate water-logged soil. Even cranberries prefer drier conditions until they are ready to be harvested.
David Robson is a horticulture educator for the University of Illinois Extension.