rhodedendron shriveling up - Ask Extension
I have a plant (I thought it was a rhodedendron but could be azalea) that leaves are shriveling downward. I assumed it was heat stress, so I have been...
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rhodedendron shriveling up #939390
Asked July 15, 2026, 2:45 PM EDT
I have a plant (I thought it was a rhodedendron but could be azalea) that leaves are shriveling downward. I assumed it was heat stress, so I have been watering. The soil is damp, but it hasn't flattened out. It does have buds. There are 2 identical varieties, but one gets more afternoon sun (they both had afternoon sun in the spring but in summer sun does reach one for a few afternoon hours). Should I water more, or leave alone until this heat wave is over? I attached 2 photos of the effected plant along with another pic of the adjacent (they are only a few feet apart) identical one that seems fine. Any advice is appreciated!
Anne Arundel County Maryland
Expert Response
This is a rhododendron (probably in the 'PJM' variety group, which all have small leaves like this and look more azalea-like when blooming), and curling leaves indicate a moisture problem. Unfortunately, the symptoms can overlap between under-watering / drought stress and over-watering and the beginnings of root rot. Rhododendron don't have high drought tolerance, nor will they handle consistently-damp soil or poor drainage well either.
During this ongoing drought and heat wave, they most likely will benefit from being watered, but how often greatly depends on soil type and how quickly it's drying out. Feel the soil around four inches deep (Rhododendron have shallower roots than most shrubs that should be checked closer to 6 inches deep). If it is becoming somewhat dry to the touch at that depth, the plant probably could use water. If it's instead damp to the touch at that depth, watering can probably wait. Sometimes plants wilt when their roots can absorb moisture fast enough to keep them fully hydrated, even in soil that is not dry. Hydrangeas are one common example of a shrub that can "flag" (wilt a bit) when it's hot, even if they're kept watered, and they recover overnight when temperatures moderate.
We can't tell from the photos if this curling is due to too much soil moisture, too little, or some other issue (like an infection) that is preventing the shrub from moving moisture up from the roots into the full canopy. Unfortunately, if it's a root rot or infection issue, there is no remedy, and the plant may decline further as the condition progresses. If the leaves curl more, turn brown, fall off, or otherwise do not recover even after the plant has been thoroughly watered (given several gallons each and some time to soak in and be absorbed), then that implies too much damage was already done and the plant won't recover. If it does look better overnight or on cooler days (or the day after a soaking rain), then it might have just been a passing drought stress reaction.
Our impression from the photos is that this is more an under-watering situation rather than over-watering, since the latter is often accompanied by a sickly yellow-green color change to the leaves and more drastic drooping (not just leaf edge curling, but the leaf hangs down more), which we don't see here. Still, the symptoms might still change, so monitor the plant and just keep an eye on its watering needs. When watering, you want to provide enough water so that the soil is rehydrated down to that four-inch depth (or more). You can check the soil a few hours after watering to see how far down the moisture seeped, in order to determine if that was enough or if you need to apply more water. Avoid wetting the leaves when watering, if possible, to reduce the risk of a fungal infection; just water the soil surface (mulch is fine).
Miri
During this ongoing drought and heat wave, they most likely will benefit from being watered, but how often greatly depends on soil type and how quickly it's drying out. Feel the soil around four inches deep (Rhododendron have shallower roots than most shrubs that should be checked closer to 6 inches deep). If it is becoming somewhat dry to the touch at that depth, the plant probably could use water. If it's instead damp to the touch at that depth, watering can probably wait. Sometimes plants wilt when their roots can absorb moisture fast enough to keep them fully hydrated, even in soil that is not dry. Hydrangeas are one common example of a shrub that can "flag" (wilt a bit) when it's hot, even if they're kept watered, and they recover overnight when temperatures moderate.
We can't tell from the photos if this curling is due to too much soil moisture, too little, or some other issue (like an infection) that is preventing the shrub from moving moisture up from the roots into the full canopy. Unfortunately, if it's a root rot or infection issue, there is no remedy, and the plant may decline further as the condition progresses. If the leaves curl more, turn brown, fall off, or otherwise do not recover even after the plant has been thoroughly watered (given several gallons each and some time to soak in and be absorbed), then that implies too much damage was already done and the plant won't recover. If it does look better overnight or on cooler days (or the day after a soaking rain), then it might have just been a passing drought stress reaction.
Our impression from the photos is that this is more an under-watering situation rather than over-watering, since the latter is often accompanied by a sickly yellow-green color change to the leaves and more drastic drooping (not just leaf edge curling, but the leaf hangs down more), which we don't see here. Still, the symptoms might still change, so monitor the plant and just keep an eye on its watering needs. When watering, you want to provide enough water so that the soil is rehydrated down to that four-inch depth (or more). You can check the soil a few hours after watering to see how far down the moisture seeped, in order to determine if that was enough or if you need to apply more water. Avoid wetting the leaves when watering, if possible, to reduce the risk of a fungal infection; just water the soil surface (mulch is fine).
Miri
