By Bert Cregg
Baldcypress is a flood-tolerant deciduous conifer that grows well in lower Michigan.
Most trees can tolerate periods of flooding while they are still dormant.
Recent heavy rains and snowmelt have led to wet basements and localized flooding across Michigan. Homeowners with standing water in their backyards often worry if there will be long-term impacts on their trees.
In late winter and early spring, many trees can handle a week or two of flooding without long-term problems. However, tree species vary widely in flood-tolerance. In fact, if we think about environmental stresses, trees vary more in flood-tolerance than any other trait. On one extreme, trees that are native to floodplains, such as cottonwoods, can withstand months of inundation. On the other extreme, upland trees such as pine, hickories and most oaks may be damaged after a week or less of flooding.
Once floodwaters recede this spring and the weather beings to warm, most trees should quickly begin to break bud and put on their spring flush of growth. Trees that have been flooded may show delayed budbreak, branch die-back, smaller than normal leaves, wilted leaves or chlorotic leaves.
For homeowners worried about trees that have been flooded, the best advice is to wait and see. Trees that are slow to leaf out are often able to catch up by late spring or early summer. Likewise, flooded trees that initially produce chlorotic or stunted leaves will often resume normal growth as spring progresses. If a flooded tree does not resume normal growth by early summer, or you suspect root damage may have affected the structural stability of the tree, you should have the tree assessed by a professional arborist.
If there are areas in your landscape where water often ponds during wet weather, Michigan State University Extension suggests a couple of options to address the situation. First, determine the source of the water. Sometimes, simply re-routing downspouts or providing a means for water to escape can eliminate the problem.
If reducing ponding is not an option, then selecting trees that are tolerant of flooding is usually the best approach. Bottomland or flood-plain species are best adapted to withstand flooding. These trees can typically tolerate several weeks of inundation, especially in late winter or early spring.
- Red maple (Acer rubrum)
- Silver maple (Acer saccharinum)
- River birch (Betula nigra)
- Hackberry (Celtis occidentalis)
- Sweetgum (Liquidambar styraciflua)
- Tupelo or black gum (Nyssa sylvatica)
- Sycamore (Platanus occidentalis)
- Eastern cottonwood (Populus deltoides)
- Swamp white oak (Quercus bicolor)
- Bur oak (Quercus macrocarpa)
- Black willow (Salix nigra)
- Baldcypress (Taxodium distichum)
- Elms (Ulmus spp.)
Dr. Cregg’s work is funded in part by MSU’s AgBioResearch.