The children’s book The Giving Tree follows a benevolent apple sapling that eventually grows into tree and also a mentor to a boy (who, eventually, becomes a man—then an old man). As it grows, the tree sacrifices its leaves, branches, and stump for the boy. What you don’t learn in the heartwarming tale, though, is that if that apple tree had come down with a case of bacteria-laden root rot, well, there would have been no story at all. Being able to identify what root rot looks like is important because it can kill not just a beloved apple tree, but also a palm plant, or fern, or really any other plant in a matter of days. So, I asked a plant expert how to spot it before the damage is done.
Below, Erin Marino, plant expert and director of marketing at plant company The Sill, offers up an SOS game plan for identifying the illness, discovering its, er, root cause, and making sure your future plants remain healthy and beautiful for many years to come.
What does root rot look like?
The first step in stopping root rot in its tracks is taking a good, hard look at your plant. “These signs can include yellowing leaves, wilting stems or foliage, mushy stems, and wet potting mix,” says Marino. “If you’re noticing these signs, you’ll want to un-pot your plant and feel its root system.” If you stick your fingers in there and find mushy, black soil or you notice that some roots have detached from the plant entirely, you likely have a case of root rot on your hands. “Systems without root rot that might just be slightly overwatered will be flexible but firm to the touch,” adds Marino.
Okay, and what causes it?
“The most common cause of root rot is overwatering,” says Marino. “As humans, we’re inclined to stay hydrated and even argue ‘the more, the better’ when it comes to water, but that’s not the case for most plants.” That’s because plants don’t absorb H2O very quickly, so if you flood them with your watering can, the soil stays wet and becomes the perfect breeding ground for rot, rot, and more rot.
“The most common cause of root rot is overwatering. As humans, we’re inclined to stay hydrated and even argue ‘the more, the better’ when it comes to water, but that’s not the case for most plants.” —Erin Marino, plant expert
“For houseplants potted in containers, if the root rot is left untreated, the root system could rot and decay completely, leading to the untimely death of the plant. If part of a garden, the root rot or corresponding fungus could spread to other plants in the vicinity,” says Marino.
Once root rot takes hold, how can I keep it from killing my plant?
Marino says it’s always ideal to catch the symptoms of root rot early (before the, bleh, fungus comes), so you can perform minor plant surgery to restore its health. “Depending on how far along the rot is, you can try to stop it before it kills the plant. To do this, first trim back the root system to the best of your ability, trying to remove the majority of the rot and mushiness. Next clean up the foliage above, removing any yellowing or dying leaves. Then repot your plant in new, dry potting soil,” she says. After that, you can’t do very much beyond simply hope that your snake plant makes it through the night.
How can I make sure all my plants have a root rot-free future?
To prevent future cases of root rot, resist the urge to over-hydrate your plant, and only pour in about a third of the total volume of the container. (If you really struggle with this, as I do, you can buy a water timer to keep yourself from getting carried away.) “Letting your plant’s potting soil dry out before watering again is key for plants to avoid overwatering. And when watering, try to be mindful of the amount of water you’re using, or opt for a planter with drainage holes for excess water to escape,” says Marino.
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