Will the sticky honeydew hurt my tree?

The honeydew itself is just waste, but it attracts ants and promotes black sooty mold. This mold blocks sunlight and can weaken the tree over time.

Can I just wash them off with a hose?

A strong blast of water can dislodge some insects, but it rarely removes them all. You usually need to follow up with horticultural oil to kill the remaining eggs.

Saucer magnolia: pests, causes and fixes

Check these first

Inspect the undersides of branches for raised bumps.
Look for sticky residue on the leaves or ground.
Check for black sooty mold on the foliage.

Likely causes

Magnolia Scale
Most likely
How to tell: You will see large, soft, brown or white bumps on the stems. The branches may also look shiny or black from sooty mold growth.
What to do: Scrub the scale off with a soft brush or apply horticultural oil during the dormant season. For active infestations in summer, use a systemic insecticide labeled for scale.
General Scale Insects
Possible
How to tell: Small, hard, shell like bumps appear on the bark. The plant may show stunted growth or yellowing leaves.
What to do: Prune away heavily infested branches to reduce the population. Apply neem oil or insecticidal soap to the remaining branches every 7 to 10 days until the pests are gone.

Pests on other plants

Find out what's wrong with your saucer magnolia

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

Scale can kill branches if left unchecked for years. A few bumps are manageable, but a full coating on the bark requires immediate action.

Stopping it coming back

Keep your tree healthy with proper watering and mulch to reduce stress. Inspect branches twice a year to catch new infestations early.

Saucer magnolia: pests? Check yours with a photo

Every plant is a little different. Take a photo of your saucer magnolia and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

Get the app · Or check it from a photo now, free

Questions people ask

Will the sticky honeydew hurt my tree?: The honeydew itself is just waste, but it attracts ants and promotes black sooty mold. This mold blocks sunlight and can weaken the tree over time.
Can I just wash them off with a hose?: A strong blast of water can dislodge some insects, but it rarely removes them all. You usually need to follow up with horticultural oil to kill the remaining eggs.

Guides to these causes

Magnolia Scale

Why are there bumps on my Saucer Magnolia branches?