Managing Flood Damaged Perennials and Annuals

When flooding occurs, it can be devastating to many things, including the landscape.  Below is advice on recovering from flood damage in perennial gardens and annual beds.

pansies under water by See More AdobeStock
Plants can often recover if submerged for only a short time.  Those that have been underwater for more than a week or so, are much more likely to see damage. (1)

Unfortunately, there is nothing you can do to change the weather. There is not even a lot you can do if your garden or landscape was flooded. At least, not until the water recedes. While many landscape plants will survive short periods of flooding, extended periods of standing water are often detrimental because of declining levels of oxygen in the soil.

As soon as possible, remove flood debris, such as plastic containers, wood, and plant debris, from the landscape. If additional soil or sediment has been deposited on the garden bed, removal may be necessary. Silt levels as deep as 1 inch could damage plants. 

Replace any mulch that has been washed away.  It is best to wait a few weeks until the soil has thoroughly dried out since mulch may impede the movement of air into the oxygen-deprived soil. After about 2 to 4 weeks, you may see a flush of weed growth.  Be sure to remove weeds before laying down a new layer of mulch.

You should know if flowering annuals will survive within one to two weeks. These plants do not have large storage reserves, so they will show damage first. Some perennials have larger above and below-ground growth, so the wait maybe 2 to 4+ weeks.  Survivability depends greatly on the species and the site. Symptoms of stress for annuals and perennials include leaf yellowing, dieback, lack of new growth, poor flowering, and/or death.

Flood Tolerant Plants

Perennial (Amsonia) in standing water
Perennials that tolerate wet conditions will recover better from flooding than those that do not. (2)

A few herbaceous perennials that prefer moist or wet soils include: 

  • Yellow Flag (Iris pseudocorus)
  • Joe-Pye Weed (Eupatorium purpureum)
  • Spiderwort (Tradescantia species)
  • Cardinal flower (Lobelia cardinalis)
  • Ligularia (Ligularia species)
  • Hardy Hibiscus (Hibiscus species)

Tender perennials that don't mind wet conditions and can even be successfully grown at the water's edge include: 

  • Canna (Canna xgeneralis
  • (Zantedeschia hybrids)

Annuals that are more likely to recover from the flooding because they tolerate wet conditions well include: 

  • wax begonia (Begonia × semperflorens)
  • spider flower (Cleome hassleriana)
  • coleus (Coleus spp.)
  • garden balsam (Impatiens balsamina)
  • impatiens (Impatiens walleriana)
  • forget-me-not (Myosotis sylvatica)
  • nasturtium (Tropaeolum majus)
  • pansy (Viola × wittrockiana)

A complete list of plants that tolerate wet conditions can be found in this article: Landscape Plants for Wet Soil Conditions.

Flood Intolerant Plants

Perennials that are most likely to be damaged by flooding because they do not tolerate wet soils include: 

  • Lambs ear (Stachys byzantina)
  • Butterfly weed (Asclepias tuberosa)
  • Russian Sage (Physostegia atriplicifolia)
  • Stonecrop (Sedum species)
  • Most spring flowering bulbs like: 
    • Daffodils (Narcissus)
    • Tulips (Tulipa)
    • Crocus (Crocus)
    • Hyacinth (Hyacinthus)

Annuals that are likely to be damaged by flood waters because they do not tolerate wet soils include: 

  • cockscomb (Celosia spp.)
  • gazania (Gazania rigens)
  • globe amaranth (Gomphrena globosa)
  • sunflower (Helianthus annuus)
  • strawflower (Helichrysum bracteatum)
  • lantana (Lantana camara)
  • rose moss (Portulaca grandiflora)
  • dusty miller (Senecio cineraria)

More Information

Photo credits: 1: Sea More/AdobeStock; 2: Cindy Haynes

Last reviewed:
June 2024