Holes in Leaves on Begonia Rex: Causes, Checks & Fixes

Quick answer

Holes in Begonia Rex (Begonia rex-cultorum group) leaves mean tissue is missing from the painted-textured blades—not natural fenestration. Rex begonias do not develop intentional splits like a Monstera; every gap is damage, disease aftermath, or chewing.

First step: Look at the hole edge. Green, moist margins point to recent mechanical tearing or active feeding. Brown, dry edges with a dark ring around the hole often mean old leaf-spot tissue fell out after the lesion dried.

For general hole mechanics on houseplants, see our holes in leaves guide. On indoor rex begonias, thin metallic painted blades brushing a windowsill or shelf lip tear more often than pests chew them—and wet foliage in humid corners can leave post-spot holes after black spots necrose.

Route to leaf miners for tunnels inside the blade, not open holes. For ragged new growth without full-thickness gaps, see thrips or distorted leaves.

When to use this page vs other Rex guides

What holes look like on Begonia Rex

Rex begonia leaves are asymmetric painted-texture blades—metallic silver, burgundy, pink, or green patterning with frilly or spiraled edges and a red underside. Holes stand out against that smooth variegated surface.

Irregular hole with dry brown rim on a rex begonia blade—check edge color to separate post-spot necrosis from fresh mechanical tears.

Mechanical tears — Clean splits or notches on one frilly edge, often on outer leaves that brush a windowsill, curtain, or nursery tag. No pest frass, no slime. Edge may brown later but the tear pattern matches a snag.

Post-spot necrosis holes — Irregular gap surrounded by dry brown or black rim where a leaf-spot lesion died and dropped out. Often on lower painted blades that stayed wet longest against the shallow pot rim. May follow water-soaked spots described in our black spots guide. Bacterial leaf spots spread on wet foliage on many ornamentals.

Caterpillar feeding — Ragged holes and notched margins; green or brown larvae tucked along the rhizome crown or midrib underside, sometimes after patio summer. Frass pellets on leaves or soil.

Slug or snail damage — Ragged holes and slime trails on pot rim or soil—mostly on floor-level patio pots, not typical year-round shelf plants. NC State lists snails and slugs among common begonia pests.

Pet chewing — Torn sections with crush marks at pet height. Begonia Rex is toxic to cats and dogs—ASPCA classifies rex begonia as toxic due to soluble calcium oxalates. Relocate the plant and contact your vet if ingestion is suspected; this guide does not replace medical care.

Thrips or aphid ragged feeding — More often silvery scarring or distorted new blades than round holes—see thrips and aphids on tender crown growth.

Painted-texture snag pattern (Rex only)

Rex begonias are rhizomatous foliage plants with thin, sparsely hairy painted blades that can reach 8 to 12 inches long on mature hybrids. That frilly metallic surface is dramatic on a windowsill—and easy to catch. When someone slides a curtain or moves the shallow pot, the frilly edge or mid-blade hooks the obstacle. The tear is usually one clean line on a single painted leaf, not random holes across the clump. Begonia leaves and flowers are fragile and should be protected from high winds—indoors, furniture edges play the same role.

Why Begonia Rex gets holes

Mechanical damage in tight spaces — Windowsills, curtain rods, and hanging tags tear thin painted blades before pests ever appear.

Wet-leaf leaf spot aftermath — Rex needs humidity but should never have wet foliage. Splash from overhead watering or misting in a steamy bathroom keeps red undersides damp; bacterial leaf spots colonize wet tissue and necrotic centers can fall out and leave holes. NC State notes bacterial leaf spots on rex types and recommends avoiding misting and overwatering.

Outdoor hitchhikers — Summer patio placement brings caterpillar eggs or slugs to pots returned indoors.

Pet access — Floor pots and low shelves put toxic foliage in chewing range.

Active chewers indoors — Less common than mechanical tears, but possible after open windows or mixed patio storage. NC State notes mealybugs, whiteflies, thrips, and spider mites as common begonia pests—they cause sticky residue and stippling more often than punched holes, but heavy infestations can weaken tissue.

Begonia does not develop bacterial “shot hole” patterns like some fruit trees indoors. Suspect tears, spot aftermath, or chewers first.

Confirm the cause in five checks

1. Edge color: Green moist = recent; brown dry with dark rim = old spot scar.
2. Location: Single outer painted blade on a crowded windowsill → mechanical. Multiple lower leaves with spot history → post-spot holes.
3. Underside at night: Flashlight on rhizome crown and midrib for caterpillars; slime on rim for slugs.
4. Pet height: Tooth marks, disturbed soil, multiple plants chewed?
5. Recent outdoor time: Patio season raises caterpillar and slug probability.

If tunnels run inside the blade without a full-thickness hole, stop here and open leaf miners.

First fix by confirmed cause

One action first: classify the hole edge before spraying anything. Cosmetic brown dry holes need culture correction, not fungicide.

Never-wet-the-rhizome spot trap (Rex only)

This pattern shows up on bathroom and kitchen rex begonias more than on open-window plants:

1. Pot sits in steamy air; shallow rhizome stays near the soil surface.
2. Lower painted blades drape over the wide shallow rim and stay damp after watering.
3. Leaf spot bacteria colonize wet tissue; spots necrose.
4. Dry centers drop out → holes with brown rims on the oldest blades touching the rim.

Fix the environment before chasing pests: bottom-water when the top 3 cm dries, drain saucers within 30 minutes, and give bright indirect light so foliage dries—see not enough light if the pot stays heavy for weeks. It is best practice to water begonias at the base and avoid the leaves. UConn recommends avoiding wet leaves to reduce powdery mildew and disease risk. Never mist rex painted blades; use a pebble tray or humidifier for low humidity without wetting foliage.

Shallow-rhizome crown hide (Rex only)

Rex begonias spread from a shallow rhizome at or just above the soil line in wide, relatively shallow pots. Caterpillars that hitchhike from patio time often rest tucked against the rhizome crown where painted petioles meet the soil—not scattered across the soil line like slug damage. At night, trace each leaf back to the crown with a flashlight on the red undersides; green larvae blend against burgundy patterning. Hand-pick the first one you find before reaching for spray. If frass keeps appearing on new growth, open the full caterpillars guide.

Recovery timeline

Holes do not close. Clean new painted leaves from the rhizome crown are the recovery marker. Rex grows moderately in season—expect two to four weeks for a firm new blade after the cause is removed.

What not to do

• Do not fungicide old dry cosmetic holes—treat active spot on surrounding green tissue instead.
• Do not mist “for humidity” on spotted or holed leaves—it spreads bacteria.
• Do not ignore pet exposure—relocate toxic rex begonia immediately.
• Do not overwater because leaves look damaged—check hole type and overwatering signs first.
• Do not compost heavily spotted blades indoors—discard in sealed bags.

How to prevent holes on Begonia Rex

• Clearance: Keep frilly painted edges away from windowsills, curtains, tags, and swinging doors.
• Dry foliage: Bottom-water at soil level only; wipe splash off spotted blades after watering.
• Spot early: Route wet expanding lesions to black spots before centers fall out.
• Quarantine patio returns two weeks; inspect rhizome crowns and undersides.
• Pet-safe placement on elevated stands—toxicity risk plus chew damage.
• Stable culture: Match watering to how fast the pot dries in your light level—rex begonias prefer moist well-drained soil but not wet leaves.

See Begonia Rex overview and problems hub.

Related Begonia Rex guides

• Black spots — wet-leaf spot before holes form
• Caterpillars — ragged chew after outdoor time
• Leaf miners — tunnels vs open holes
• Thrips and aphids — ragged new growth
• Distorted leaves — unfurl damage without holes
• Brown tips — margin damage, not gaps
• Watering and light — dry-down rhythm in bright rooms

Conclusion

Holes in rex begonia leaves are usually snags, spot aftermath, or occasional chewers—not a mystery disease. Read the hole edge first, reposition away from window traps, keep painted foliage dry, and treat active black spots before they necrose through the blade. Watch for clean new metallic-patterned leaves from the rhizome crown over the next month; that is your proof the fix worked.