What Is the Sticky Stuff Falling From Trees?

Most of the time it’s honeydew—sugary droplets excreted by sap‑sucking insects like aphids and scale—rather than the tree’s own sap. Less commonly, the stickiness comes from natural sap or resin leaking from wounds, flower nectar drip, guttation from leaf edges, or a disorder such as slime flux. Understanding the source helps you decide whether to simply rinse things off, boost tree health, or call an arborist.

The usual culprit: honeydew

Honeydew is a clear, sugary liquid produced by insects that feed on tree sap, including aphids, scale insects, whiteflies, psyllids, and some leafhoppers. These insects tap into the phloem and expel excess sugars, which fall like a “sticky rain” onto cars, decks, and sidewalks. Black sooty mold often grows on surfaces coated with honeydew, turning leaves and objects dark but usually not harming the tree directly. Ants are frequently seen farming these insects for honeydew and will defend them from natural predators, prolonging outbreaks.

Other possibilities

Not all stickiness is honeydew. Trees can ooze their own liquids under certain conditions. Resin or sap can seep from wounds or pruning cuts, particularly on conifers and maples. Brief periods of nectar drip can occur when flowering trees (such as linden/basswood) produce excess nectar. Guttation—tiny droplets at leaf tips—can happen overnight in humid, well-watered conditions. Slime flux (also called wetwood) is a bacterial issue that causes sour-smelling, sometimes sticky ooze from trunks or large limbs. Rarely, “drippy blight” has been reported on oaks, a sticky exudation associated with scale insects and bacterial infection.

How to tell what you’re dealing with

The following points can help you distinguish honeydew from sap, resin, or other exudates by looking at appearance, timing, smell, and where the liquid originates.

• Honeydew: Fine “rain” of clear, sweet, very sticky droplets from the canopy; often worst in late spring through summer; sooty mold grows on leaves and objects below; aphids/scale visible on undersides of leaves and twigs; ants frequently present.
• Resin/pitch (mostly conifers): Thicker, amber or milky beads from specific wounds or bark cracks; pine-like odor; hardens into a brittle bead; often localized rather than raining broadly.
• Sap bleed (maples, birch, others): Noticeable after pruning or bark injury, especially in early spring; may be pale to yellowish and attract bees/wasps; flows from a discrete cut or wound site.
• Guttation: Tiny droplets at leaf tips/edges early morning; appears after humid nights or heavy watering; dries quickly and doesn’t usually coat cars or pavement broadly.
• Slime flux/wetwood: Oozing streaks down the trunk with sour or fermenting smell; bark is stained; may attract insects; originates from internal trunk pressure rather than the canopy.
• Nectar drip (flowering period): Short-lived during bloom; sweet scent; often coincides with heavy pollinator activity; stops when flowers fade.

If you see a canopy-wide sticky rain with sooty mold and ants, honeydew is the likely source; single-point leaks, strong odors, or resin beads usually indicate sap, resin, or flux.

Is it harmful?

Honeydew itself isn’t toxic and rarely threatens an otherwise healthy tree. However, heavy infestations can stress trees, reduce vigor, and encourage sooty mold that shades leaves. Resin or sap bleeding can be a normal response to injury, but persistent pitch flow on conifers can signal bark beetles or canker disease. Slime flux indicates internal bacterial infection; it’s unsightly but often managed by improving tree vigor rather than invasive treatments. Sticky residues can attract ants, wasps, and bees and make hard surfaces slippery, so cleanup is sensible even when trees aren’t in danger.

What you can do

Management depends on the cause. Start with the least disruptive options and escalate only if the tree’s health or safety is at risk.

• Rinse and wait: Spray leaves with plain water to dislodge honeydew and insects; rinse cars, furniture, and walkways to reduce stickiness and sooty mold. Natural predators (lady beetles, lacewings, parasitoid wasps, hoverflies) often reduce outbreaks in a few weeks.
• Disrupt ant protection: Use ant baits on the ground and prune ant “bridges” so predators can access aphids/scale. Avoid sticky trunk bands unless properly guarded—they can trap birds and beneficials.
• Prune selectively: Remove heavily infested twigs/branches during the tree’s appropriate pruning window; sanitize tools between cuts. Avoid heavy pruning in spring for “bleeder” species like maples and birches.
• Adjust care: Water deeply but infrequently; mulch properly (2–3 inches, not touching trunk); avoid high-nitrogen fertilizers that spur lush, pest-prone growth.
• Horticultural oils/soaps: In late winter (dormant oil) or during the growing season per label directions, oils and insecticidal soaps can suppress aphids and soft scales with relatively low non-target impact. Thorough coverage is key.
• Systemic insecticides: Use only when justified and timed to avoid bloom; many systemics (e.g., some neonics) are restricted in certain regions and can harm pollinators. Consult a certified arborist and local regulations; consider trunk injections over soil drenches near flowering plants.
• For sap/resin and flux: Don’t plug or seal wounds; avoid wound paints. Improve tree vigor, correct irrigation, and reduce root stress. Seek diagnosis if pitch tubes (conifers), cankers, or extensive dieback are present.

Most homeowners can manage honeydew with rinsing, ant control, and patience. Reserve chemical treatments for persistent, tree-threatening infestations, and always follow local rules and product labels.

Cleaning sticky deposits safely

Prompt, gentle cleaning protects finishes and reduces slipping hazards without damaging surfaces or nearby plants.

• Vehicles: Wash with warm water and car shampoo; use a detailing clay bar for stubborn spots; follow with a protective wax or sealant. For tough residues, a soft microfiber with diluted isopropyl alcohol (test first) can help. Avoid abrasives and harsh solvents.
• Outdoor furniture/decks: Use warm soapy water; rinse thoroughly. For wood, avoid strong solvents that strip finishes; consider a mild deck cleaner and re-seal if needed. Covers or moving items during peak drip can reduce cleanup.
• Walkways/patios: Rinse to reduce slip risk; a mild detergent helps lift sugar. Avoid bleach on vegetated areas; protect nearby plants from runoff.

Regular rinsing during peak drip periods prevents buildup and limits sooty mold growth, making later cleanup easier.

When to seek professional help

Some symptoms point to issues beyond nuisance stickiness and warrant diagnosis by a certified arborist.

• Noticeable canopy thinning, branch dieback, or early leaf drop.
• Persistent heavy honeydew year after year, especially with ant infestations you can’t control.
• Conifers with pitch tubes, boring dust, or bark that peels easily—possible bark beetles.
• Trunk ooze with foul odor or extensive staining (possible slime flux or canker).
• Large wounds, recent construction/grade changes, or soil compaction affecting roots.
• High-value specimen trees or trees over structures, where risk and liability are higher.

A professional can accurately identify pests or disorders, recommend targeted, pollinator-safe treatments, and advise on pruning and long-term care.

Tree species commonly linked to sticky drip

Some trees are frequent hosts for honeydew-producing insects or are prone to other kinds of exudation.

• Maples, sycamores, elms, willows, poplars, birches: Often host aphids/scale; spring sap bleed is common in maples and birches after pruning.
• Lindens/basswood (Tilia): Heavy nectar production and aphids can cause intense, short-lived drip during bloom and into summer.
• Oaks: Susceptible to various scale insects; “drippy” exudates occasionally reported in association with scale and bacterial infection.
• Crape myrtle: Frequently affected by aphids and bark scale, leading to prolific honeydew and sooty mold.
• Conifers (pines, spruces, firs, hemlocks): Resin exudation from wounds; hemlock woolly adelgid and other pests can contribute to honeydew.
• Citrus and hackberry: Whiteflies, scales, and psyllids (including lerp psyllids on eucalyptus in some regions) produce heavy honeydew.

Knowing your tree species can quickly narrow the likely cause and best response.

Summary

That sticky drizzle under your tree is usually insect-produced honeydew, not leaking sap. Confirm by looking for aphids/scale, ants, and sooty mold. In most cases, rinse surfaces, encourage natural predators, and manage ants; prune and consider oils if needed. Localized amber beads or foul-smelling trunk ooze point to sap/resin or slime flux and may merit an arborist’s assessment. With correct identification and simple steps, you can minimize the mess while keeping trees and pollinators in mind.

Why is my tree dropping sticky stuff?

Your tree is likely dripping sticky stuff due to an infestation of sap-sucking insects, such as aphids, scale insects, or mealybugs, which produce a sugary waste product called honeydew. This honeydew, not sap, drips from the leaves and can cause surfaces below to become sticky. The sticky residue can also attract other insects, like ants, and promote the growth of black sooty mold. 
This video explains the difference between honeydew and sap: 1mCBC News SaskatchewanYouTube · Aug 25, 2017
Understanding the sticky substance:

• Honeydew: Opens in new tabThe sticky substance is a form of insect excrement containing sugars from the tree’s sap. It’s a common byproduct of aphids, scale, and other sap-sucking insects. 
• Sooty Mold: Opens in new tabThe honeydew provides food for a black fungus called sooty mold, which grows on the leaves and can block sunlight. 

What to do about it:

1. Check for pests: Look for tiny insects like aphids (often green or black) or scale insects (which can look like brown bumps) on the leaves and branches. 
2. Consider natural controls: A strong spray of water from a garden hose can dislodge aphids from the tree. Ladybugs and other beneficial insects are natural predators of aphids and can help keep populations in check. 
3. Wash it off: You can wash the honeydew from surfaces like patios and cars with soap and water to remove the sticky residue. 
4. Consult an arborist: If the infestation is severe or the tree is large, a professional arborist can diagnose the problem and recommend appropriate treatments. 

What are the sticky things that fall from trees?

honeydew
If you spend a lot of time in nature, chances are you already had an encounter with a tree dropping a gummy goop that looks just like sap. However, that sticky liquid oozing out of trees is actually insect waste, and it’s called honeydew.

Why is the tree sap so bad this year?

The “bad sap” you’re seeing is likely honeydew, a sticky, sugary byproduct from sap-feeding insects like aphids, scale insects, or mealybugs. These pests consume tree sap and excrete the undigested sugar, which then drips onto surfaces. While a small amount of real tree sap is normal, an abundance of sticky residue, especially on leaves and cars, signals an infestation. A tree might also be leaking its own sap in response to pests, diseases, or injury, which can look like oozing or pitch tubes. 
Causes of Sap-Like Residue

• Insect Infestations (Honeydew):
  • Aphids: These insects suck sap from leaves and excrete a sticky honeydew. 
  • Scale Insects: Like aphids, they feed on tree sap and produce honeydew. 
  • Mealybugs: These also feed on sap and produce honeydew. 
  • Result: This results in a sticky substance that can turn black due to sooty mold. 
• Tree Defense (Real Sap):
  • Pest Damage: Trees produce sap to protect themselves from insects that bore into the bark. 
  • Wounds and Injuries: Damage from pruning, freezing, or physical impacts can cause sap to ooze as the tree heals. 
  • Diseases: Infections like bacterial canker or wetwood can also cause excessive sap production. 

How to Identify the Cause

• Look for honeydew: If you see a sticky, sugary substance on leaves, cars, or patios, it’s likely honeydew from an insect infestation. 
• Check for insects: Look closely at the leaves and branches for clusters of aphids, scale, or mealybugs. 
• Examine the tree for wounds: Inspect the bark for boreholes or pitch tubes, which are signs of beetle activity. 
• Look for other symptoms: Wilting branches or sour-smelling, grayish residue can indicate a bacterial infection like bacterial canker or slime flux. 

What to Do

• Consult an Arborist: An arborist can properly diagnose the issue and recommend the best treatment. 
• Promote Tree Health:
  • Water and Mulch: Keep trees watered to maintain soil moisture, and apply a layer of mulch to help retain it. 
  • Prune Properly: Pruning can provide an entry for bacteria, so ensure it’s done correctly. 
• Address Pests: Treatment options may include using trunk wraps, trunk injections, or controlling the insect population, but these should be guided by an arborist. 

What is the sticky stuff oozing out of trees?

Trees can ooze sap from their trunk or branches when wounded or when infected by fungal diseases. But the most common cause for sticky liquid dripping from trees is actually honeydew, a sugary substance produced by aphids, scales, and other piercing-sucking insects when they feed on tree sap.