Plant care guide
Why Is My Begonia Dropping Leaves? Check the Type First
Updated
Why is my Begonia dropping leaves?
Begonias drop leaves after cold, a sudden move, or mix that is kept too wet or allowed to dry out. Which kind of begonia you have matters: tuberous begonias die back after flowering, wax begonias brought indoors shed while they adjust, and rex begonias decline in dry air.
What to do first
Identify the type first, then check the mix and the temperature. If the mix is wet and stems are soft at the base, stop watering and check the roots. If the plant was recently moved or chilled, keep it warm, steady and out of drafts.
Begonia leaves are fragile, and a plant that sheds them can look ruined in a week. Before you change anything, work out which begonia you have. NC State Extension’s begonia profile describes a genus of more than 2,100 species. Growers sort them into wax, tuberous, cane, rhizomatous and rex types, and they drop leaves for different reasons.
Check the type
| Type | How to recognise it | Leaf drop to expect or suspect |
|---|---|---|
| Wax (semperflorens) | Small, bushy, waxy leaves, constant small flowers | Shedding after a move indoors in autumn |
| Tuberous | Large showy flowers, grows from a tuber | Dieback after flowering |
| Cane, including angel wing and B. maculata | Upright, bamboo-like stems | Loss of lower leaves with age |
| Rex and rhizomatous | Grown for patterned leaves, creeping rhizome | Decline in dry air or cold |
| Lorraine and Elatior | Compact flowering pot plants | Decline after flowering |
Tuberous begonias. Clemson Extension’s indoor begonia factsheet says to stop watering tuberous begonias in autumn. At the end of the flowering season, cut off the shoots and store the tubers dry. Leaves fading and falling then is the plant’s cycle, not a disease.
Lorraine and Elatior begonias. Clemson says these are usually discarded after flowering, though they can be cut back to within 8 cm (3 in) of the crown and restarted.
Cane begonias. NC State says cane types often lose their lower leaves and come to resemble canes. For the polka dot begonia, see our Begonia maculata dropping leaves guide.
Causes that apply to every type
Cold. NC State says most cultivated begonias do not tolerate temperatures below 13 °C (55 °F). Clemson keeps foliage begonias at 19–23 °C (66–73 °F), with nights no lower than 13 °C (55 °F). Clemson’s disorders factsheet lists chilling as a cause of leaf drop.
A sudden move. Clemson says wax begonias grown outdoors can be dug and brought indoors in autumn. Iowa State University Extension’s diagnosis guide says leaf drop follows a quick move from bright to darker light. Clemson adds that drop after a big change should last about three weeks.
Too wet. NC State calls begonias highly susceptible to root rot and lists Pythium root and stem rot. Clemson says to keep the mix evenly moist, let it dry only slightly, avoid waterlogged soil, and never leave the pot in a saucer of water. See our begonia root rot guide if stems are soft at the base.
Too dry. Clemson lists under-watering as a leaf-drop cause too. A small pot packed with roots dries fastest.
Dry air for rex begonias. NC State says rex begonias need humidity above 75% and decline when it is too low. Clemson suggests raising humidity around them rather than misting the leaves. For crisp rex leaves, see rex begonia crispy leaves.
Disease and pests
UC IPM’s begonia pest management page says bacterial leaf spot starts as small, water-soaked spots, and leaves fall early when spots are numerous. It is favoured by splashing water. UC IPM also lists Botrytis blight and powdery mildew, which it notes is common as plants senesce in autumn. NC State advises watering at the base and keeping the leaves dry.
NC State and Clemson list mealybugs, whiteflies, thrips, scale and spider mites. Clemson’s outdoor begonia factsheet warns that begonias may be sensitive to insecticidal soaps, so test a small area before spraying the whole plant. For white powder on leaves, see our begonia powdery mildew guide.
What to do
- Name the type. Tuberous dieback after flowering needs a dry rest, not rescue.
- Feel the mix. Water only when the surface has dried slightly. Empty the saucer.
- Check stem bases. Soft or dark stems at the soil line mean a root check.
- Move it somewhere warm and steady, in bright light out of direct sun for foliage types, as Clemson advises.
- Water the mix, not the leaves. Pick up fallen leaves and remove spotted ones.
- Treat pests only after confirming them on leaf undersides.
Judge recovery by new leaves at the stem tips. For a side-by-side of the groups, read our begonia types and care guide. More pages are on the begonia hub.
References
- NC State Extension Gardener Plant Toolbox: Begonia
- Clemson Cooperative Extension, HGIC 1552: Growing Begonias Indoors
- Clemson Cooperative Extension, HGIC 1159: Begonia
- Clemson Cooperative Extension, HGIC 2251: Houseplant Diseases & Disorders
- UC Statewide IPM Program: Begonia, Floriculture and Ornamental Nurseries Pest Management Guidelines
- Iowa State University Extension: Diagnosing Houseplant Problems from Improper Environmental Conditions
How this guide was put together: NC State Extension, Clemson Cooperative Extension, UC Statewide IPM Program and Iowa State University Extension guidance.