Flooding can wreck havoc with your garden plants. Roots suffocate in standing water and, if submerged long enough, will die. Large, healthy plants or bog loving plants have a better chance of surviving flood damage than do young or ornamental plants.
Although it is unlikely plants will survive a flood, there are precautions a homeowner can take to protect plants before and after flooding occurs.
After a flood, be patient and let plants heal. Once the water recedes, check for broken limbs and remove them. Leaves may be lightly sprayed to remove any debris.
Not all flood damage is immediate. It can take years for stress or rot to kill a plant. Look for curled, wilted leaves with yellow edges. This indicates water stress. Also, notice any new fungi or cankers that emerge on plants or mushrooms that sprout at the base of a plant. These are signs of rot. Insect damage may also arise. Herbicides and fungicides, used as directed, may be applied to limit further damage.
Take a soil test before adding fertilizer near the plants. Soil composition and nutrient levels may have changed significantly after flooding, and a test will reveal the right amount of fertilizer needed. Applying to much fertilizer to a stressed plant could harm it further.
Tips to protect gardens in flood-prone areas:
- Amend clay soils with mulches, sticks or rocks to improve drainage.
- Create berms to divert water away from tender perennials.
- Build ditches, swales or furrows to divert runoff water away from yards. Contact the local utility or road department for advice. They may even build a ditch if property is donated.
- Make rain gardens or ponds to slow runoff and act as a water filter.
- Plant water-loving plants: willows, bald cypress, flag Iris, elephant ears, elderberries and red or silver maples. Contact the County Extension Agent or local Master Gardener Program for a list of water-loving plants that are native to the area.
- Use raised beds or moveable containers to keep flood waters away from plants.
- Wherever possible, create permeable landscapes to slow runoff.
Careful landscape planning, use of appropriate plants, and gentle care after a flood, will protect gardens and help plants survive in flood-prone areas.