Understanding extrafloral nectaries, honeydew, guttation, and more.
One day you touch your plant and your fingers come away sticky.
You look closer: there are shiny droplets on the stems, maybe a faint film on the leaves.
Your first thought? “Pests!”
But not all stickiness is a bad sign.
Plants can secrete liquids for several very different reasons — some harmless, others warning signals that it’s time to act.
At Planteka, we love helping you understand what your plants are telling you. Let’s go through the main causes of sticky leaves, how to tell them apart, and when to worry.
1. Extrafloral nectaries — a natural self-defense
Let’s start with the most surprising reason.
Many plants, including Philodendron, Ficus, Hibiscus, Passiflora, Alocasia and some peonies and cherries, naturally produce small droplets of sugary nectar from glands outside their flowers. These are called extrafloral nectaries (EFNs).
EFNs are part of the plant’s defense strategy. The nectar attracts ants, wasps, or other beneficial insects that in turn protect the plant from herbivores such as caterpillars or aphids.
Indoors, those droplets often appear as tiny, clear or amber beads along stems or at leaf bases. They feel sticky but aren’t harmful. If you wipe them away, they often reappear in the same exact spot a few days later.
How to recognize them
✅ Clear, symmetrical droplets (often where the leaf joins the stem).
✅ The plant looks healthy otherwise.
✅ No visible pests or mold.
💡 Note from Planteka: EFNs are like your plant’s tiny sugar bar for allies — not a sign of disease. Wipe gently if sticky, but don’t treat.
2. Honeydew — the sign of sap-sucking pests
This is the sticky situation most people worry about, and with good reason.
Honeydew is the waste product of aphids, mealybugs, scale insects, and whiteflies — all of which feed on plant sap. The sugar-rich residue coats leaves and nearby surfaces, making them sticky and shiny.
If left untreated, honeydew often leads to black sooty mold, which thrives on the sugary layer and blocks light from reaching the leaves.
How to recognize it
⚠️ Sticky film scattered unevenly over leaves or on furniture below the plant.
⚠️ Visible pests: white cottony spots (mealybugs), brown bumps (scale), clusters of green or black dots (aphids).
⚠️ Leaves may curl, yellow, or weaken over time.
What to do
- Wipe leaves with a damp cloth to remove residue.
- Inspect all leaf undersides and stems.
- Treat with neem oil spray (see the recipe here).
- Repeat weekly until no pests remain.
3. Guttation — water droplets at the leaf tips
If your plant forms watery droplets at the very tips or edges of leaves, especially overnight, that’s probably guttation.
Guttation happens when roots absorb more water than the plant can transpire, pushing out excess through special pores called hydathodes. The liquid is mostly water mixed with minerals and sugars, which can feel slightly sticky when dry.
You’ll see this often in Alocasia, Monstera, Syngonium, peace lilies, and other tropicals.
How to recognize it
💧 Drops appear at the tips or serrated edges, not the base.
💧 Usually early in the morning or after heavy watering.
💧 Leaves otherwise healthy.
What to do
Nothing! Guttation is harmless. Just avoid watering late at night or leaving plants in soggy soil — excess guttation may indicate overwatering or high humidity.
4. Nectar and resin from flowers or buds
Flowering plants such as Hibiscus, Ficus, Citrus, and Schefflera sometimes exude sticky nectar or resin from flower buds or young shoots.
This can look like pest residue, but if it appears only around blooms or new growth, and no insects are visible, it’s likely floral nectar or natural resin.
It helps protect developing tissue from herbivores and dehydration.
How to recognize it
🌸 Sticky only near buds or new leaves.
🌸 No damage, pests, or mold.
🌸 Usually seasonal and short-lived.
Simply clean with a damp cloth; it’s part of normal growth.
5. Sap leaks or mechanical injury
Sometimes a plant becomes sticky because it’s leaking sap — usually after pruning, breakage, or if stems are bent. The sap of plants like Ficus, Euphorbia, or Hoya is naturally sticky and can ooze for several hours after damage.
How to recognize it
🌿 A single spot of thick, milky or amber fluid.
🌿 Appears where tissue was cut or broken.
🌿 Doesn’t spread.
Let the area dry naturally. Avoid overhandling or cutting during high sap pressure periods (warm, humid days).
💡 Note from Planteka: Sap from Ficus and Euphorbia can irritate skin — always wash hands after contact.
How to tell what’s what?
| Sticky cause | Location | Texture / look | Action needed |
|---|---|---|---|
| Extrafloral nectaries | Leaf joints, petioles, veins | Clear or amber beads, symmetrical | Harmless; wipe gently |
| Honeydew (pests) | Random patches, undersides | Shiny film, often with insects | Treat for pests |
| Guttation | Leaf tips or edges | Watery, appears overnight | Normal; reduce watering slightly |
| Flower nectar / resin | Around buds or new leaves | Sticky near blooms | Normal; clean gently |
| Sap leak / injury | Cut or broken stems | Thick, milky or amber drop | Let heal; handle carefully |
When to worry
You only need to worry if:
- Sticky residue covers large areas.
- You see visible insects (aphids, mealybugs, scale).
- Leaves are curling, yellowing, or showing mold.
Otherwise, mild stickiness — especially at consistent points — is usually normal plant physiology, not a crisis.
The beauty of observation
Understanding why your plant feels sticky turns confusion into connection.
That small droplet might be your plant’s way of defending itself, healing, or simply releasing excess water.
At Planteka, we believe that plant care starts with observation. The more you notice, the more you learn.
👉 Join our plant care workshops in Barcelona, Madrid, or Valencia, or explore our online gardening course for beginners to learn how to read your plants’ signals — from sticky leaves to root health.
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