Plant care guide

String of Hearts Yellow Leaves: Overwatering, Rot or Light?

Updated

Why are my String of hearts leaves turning yellow?

Yellow leaves on string of hearts most often point to overwatering and root or basal rot, especially in winter when the plant is resting. Pale, washed-out leaves with long gaps between them point to low light instead.

What to do first

Check whether the mix is still wet. If it is, stop watering, inspect the roots and tubers, and let the pot dry completely before the next watering. If the mix is dry and the leaves are pale and widely spaced, move the plant to brighter light.

Yellow leaves on a string of hearts are worth acting on quickly. This trailing succulent stores water in its leaves and tubers, and it handles drought far better than wet roots. University of Wisconsin–Madison Extension says it is easily killed by overwatering.

NC State Extension links yellowing directly to that problem: its Ceropegia woodii profile says overwatering can cause root rot and yellowing of the leaves. Start with the pot, then look at light and pests.

Check the cause

Wet mix and rot

This is the first thing to rule out. Look for:

  • Mix that is still damp days after watering.
  • Yellow leaves spread along the vines rather than one or two old leaves.
  • Stems that are soft or dark where they meet the soil.
  • Soft, dark roots or mushy tubers when you tip the plant out.

The RHS notes the plant is vulnerable to basal rot if too wet in winter. University of Maryland Extension says root rots cause yellowing, browning and wilting, sometimes even when the mix is moist. Rotted roots are brown to black and soft.

Winter is the risky season. NC State says string of hearts is dormant over winter and watering should be reduced even further. Wisconsin recommends a winter rest with less water and no fertilizer.

Too little light

Low light usually shows as pale rather than truly yellow leaves. Wisconsin says leaves are darkly colored with distinct marbling in strong light, but turn light green without enough light. NC State adds that large gaps between leaves mean the plant isn’t getting enough light.

If the mix is dry and healthy-looking but the vines are long, bare and pale, light is the likelier cause.

Too much sun or a dry spell

NC State says too much sunlight scorches leaves, and underwatering causes wilted leaves. Scorch appears on the most exposed leaves after a move into stronger sun. Wisconsin advises acclimating plants gradually before moving them outdoors.

Pests

Wisconsin names mealybugs as the main pest. NC State and the RHS add aphids and scale. Check leaf joints and stems for white, cottony clusters or small bumps.

Normal leaf loss

Iowa State University Extension notes that houseplant yellowing often has several causes acting together, including cold drafts and sudden light changes. Its houseplant diagnosis guide adds that a few older leaves shed by an otherwise healthy plant are normal.

What to do

  1. Stop watering if the mix is damp. Don’t add water to a yellowing plant until you know the mix is dry.
  2. Tip the plant out and look. Healthy roots and tubers are firm. Remove any that are soft or dark.
  3. Repot if the mix stays wet. Wisconsin recommends a well-drained cactus and succulent mix, or potting mix with extra perlite. Use a pot with a drainage hole that isn’t much bigger than the root ball. NC State and Wisconsin both say the plant likes to be crowded.
  4. Save healthy vines if rot is advanced. Maryland Extension advises taking cuttings only from healthy tissue. Firm vines with tubers can be rooted in a fresh pot.
  5. Let the pot dry out completely before watering again, as NC State advises. Then water deeply.
  6. Fix the light. Wisconsin suggests a west- or south-facing window. Keep the plant above 16 °C (60 °F) in winter.
  7. Isolate the plant and treat pests once you have identified them.

Judge recovery by new growth along the vines, not by the leaves that have already yellowed.

Prevent it

  • Water only when the mix is completely dry, then soak it. Our soak-and-dry guide for string of hearts explains the method and the winter adjustment.
  • Cut back watering further in winter, as NC State and Wisconsin advise.
  • Fertilize at most monthly while the plant is actively growing, at half strength, per Wisconsin. Skip feeding in winter.

For general care, see the string of hearts hub and our guide to yellow houseplant leaves.

Other string of hearts problems we cover: propagation, dropping leaves, leggy growth.

References

How this guide was put together: NC State Extension, University of Wisconsin–Madison Extension, RHS, University of Maryland Extension and Iowa State University Extension guidance.

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Knowledge record: pg-string-of-hearts--yellow-leaves