Why is my ivy turning yellow?

This was actually a question from one of our librarians, who had received a potted ivy plant which she had been keeping by the library window. The plant was getting lots of sunlight, but the leaves were turning yellow. We checked The House Plant Encyclopedia by Ingrid Jantra and Ursula Krüger, What’s Wrong with My Houseplant? by David Deardorff and Kathryn Wadsworth, and Kristi Waterworth’s “Ivy Turning Yellow” article on GardeningKnowHow.com to find out why.

According to Jantra and Krüger, ivy leaves may turn pale if they’re getting too much light, but, in general, yellow leaves are caused by too little light, a nutrient deficiency, or too much watering. Deardorff and Wadsworth agree. Evidently, it’s difficult to tell exactly what causes yellow leaves – they’re a symptom of some sort of problem, anything from fungus, insects, or a bacterial infection to the issues mentioned above. Waterworth adds that it may be something in the ivy’s environmental stressing it out. Dry air, high levels of salt in the soil (either from tap water or overfertilizing), or a draft can all make an ivy’s leaves go yellow.

Our librarian guessed that it may have been a draft, since her ivy sat in a cold window. She has since moved it and is waiting to see if its condition improves.

Why do my air plants keep dying?

“I thought air plants were supposed to be low-maintenance, but mine keep dying. What am I doing wrong?”

Tillandsias, commonly known as air plants, are often marketed as needing no care. However, they are still living plants (part of the bromeliad family, which also includes pineapples), and, as such, they need light and water to survive. We have a copy of Air Plants: The Curious World of Tillandsias by Zenaida Sengo, which has good information on tillandsia care and gives some hints about what our patron may have been doing wrong.

Our patron’s plants may not have been getting enough water. Sengo recommends either misting them 3-7 times a week, dunking them in water for a few minutes 2-4 times a week or every 7-10 days, depending on the variety of plant, or submerging them for an hour or two each week. An under-watered plant with begin to brown and crisp up at the tips, or its leaves may curl in on themselves.

However, air plants are also prone to rot, so if they weren’t aired out properly, that may have been what did them in. Sengo recommends shaking the water out of tillandsias, and making sure to place them on top of rocks or branches as opposed to something that retains water like soil or moss. Also, while tillandsias look good in terrariums, gardeners need to be especially careful not to overwater them – air in terrariums doesn’t circulate well, so it takes longer for the plant to dry out.

A tillandsia that isn’t getting enough light may have discolored leaves, or it may show no signs of distress until a thorough watering causes it to abruptly fall apart. While the gardener may think that watering was the cause of death, the lack of light was the real problem, preventing the plant from performing its normal functions. Tillandsias need as much bright, indirect light as possible, and Sengo suggests a few hours of gentle direct sunlight as well, such as the morning light from an east-facing window. 

Can you save an overwatered plant?

If your potted plant is looking yellow and wilted even though you’ve been watering it regularly, it’s possible that you’ve been watering it too much. Too much water stresses out your plant, makes it more susceptible to disease, and can cause the roots to rot. Fortunately, you still may be able to save it.

Move the plant to the shade, since it won’t be able to take in all the water it needs to be in proper sun. If the soil doesn’t seem to be drying out quickly enough, you can repot the plant entirely. (With succulents and other plants that need very little water, you can even leave the plant lying out on paper towels or something other absorbent surface while the root ball dries out.)

Make sure that your plant is draining well. If there aren’t drainage holes in the bottom of the pot, you can drill a few or else repot the plant. Mixing in vermiculite can help make the soil less dense.

If you’re concerned about root rot, repot the plant, dispose of the old soil, and sterilize the old pot. (Root rot is caused by a fungus, and you want to be careful to keep from spreading it to other plants. Wash your hands between handling infected and healthy plants.) You can try trimming away the diseased roots (they will be recognizable by their weak, mushy texture) or treating the plant with a fungicide.

We got our information on rescuing overwatered plants from Gardening Know How, Proven Winners, Ortho’s Guide to Successful Houseplants, and The Houseplant Expert: Book Two. Both books are available at the Newton Falls Public Library, along with others like Tovah Martin’s The Indestructible Houseplant.

What's wrong with my plant?

“My string-of-pearls plant feels sticky and has patches of what looks like white fuzz on it. What’s wrong?”

Looking through several books, including David V. Alford’s Pests of Ornamental Trees, Shrubs, and Flowers, The Organic Gardener’s Handbook of Natural Insect and Disease Control, and Insect Disease and Weed I.D. guide, we diagnosed the plant with mealybugs. Female mealybugs are covered with a fluffy white wax, and they lay their eggs in similarly fuzzy-looking white wax sacs. (The male insects have wings and are small and difficult to see.) Mealybugs eat sap and secrete something called honeydew, which gives the plant a sticky feel. (Ants also like to eat the honeydew, so a mealybug infestation may give way to an ant infestation.) According to Pippa Greenwood’s Pests and Diseases, succulents (like the string-of-pearls) are some of the most common mealybug hosts.

Our gardening books provided a wealth of ideas for combating the infestation. Debra Lee Baldwin’s Succulents Simplified suggests moving the plant away from any others to somewhere with good air circulation and spraying it down with a mix of isopropyl alcohol and water until all the bugs are gone. Introduce ladybugs, parasitic wasps, or mealybug destroyers, if possible, as they’re all some of the mealybug’s natural predators. Commercial pesticides are also available. If a spray doesn’t seem to be penetrating the mealybugs’ protective waxy coating, try using a small paintbrush to dab it directly on them. The Plantfinder’s Guide to Cacti and Other Succulents by Keith Grantham and Paul Klassen and Cacti and Succulents by Hans Hecht both suggest painting the mealybugs with denatured alcohol or an alcohol/dish soap mixture to remove the waxy coat. Leaf shine spray is also effective against mealybugs, but it will also remove the pleasant powdery bloom on any plant with glaucous leaves.

How Do I Take Care of My Boston Fern?

“I’m getting ready to bring my houseplants back inside for the winter, and I’m not sure how to take care of a large Boston fern. Do you have any books that will help me?” The staff of the Newton Falls Public Library enjoys plants, as can be seen by the ones arranged throughout the library, and understands how important it is to know how to properly care for them.

Our search began in the section filled with books about houseplants. The Pitiful Gardener’s Handbook: successful gardening in spite of yourself by Connie Eden & Tracy Cheney had an appealing title, but did not deal with the problem at hand. In many of the books the Boston fern is listed not by its common name but as Nephrolepis exaltata ‘Bostoniensis.’ Ortho’s Guide to Successful Houseplants and The Complete Guide to Indoor Gardening by Jenny Rawforth and Val Bradley respectively have sections about the care of this type of fern. It requires indirect sunlight or moderate light, and normal room temperature and humidity. The two differ in reference to how wet to keep the soil. Ortho’s Guide to Successful Houseplants [p.270] recommends allowing the “plant to approach dryness before watering, then water thoroughly and discard drainage.” The Complete Guide to Indoor Gardening [p. 134] says to “keep moist at all times.” The RHS Encyclopedia of House Plants Including Greenhouse Plants [p. 359] by Kenneth A. Beckett seems to take a slightly different perspective with the admonition to “allow the surface of rooting medium to dry out between watering.”

The Ortho’s Guide also advises the home gardener to groom the fern by picking off the yellowed fronds and to shape the plant with “light pruning or clipping at any time.” When moving the plant back into the house after a summer spent outdoors, the owner may notice that its leaves are dropping or it becomes spindly because of low light. The Complete Guide to Indoor Gardening notes that dry air can cause browning. If that happens it is suggested that the plant owner set the pot “on a tray of moist pebbles to increase humidity.”


Armed with this information our patron seems prepared to maintain a healthy fern until it can be returned to the outdoors.