Hydrangeas turning brown - what can I do?
My hydrangeas have been turning brown for the past two weeks, even though I water them regularly. The leaves look kind of dried out, but the soil is moist. Could it be the heat, or do I have a pest problem?
4 answers
★ Best answer
Don't water too much - that's the first rule. Moist soil and brown leaves often point to waterlogging, even if the top feels dry. In this heat, water evaporates quickly at the surface, but it pools down below, and then the roots start to rot. Pests are possible, but less likely - check the undersides of the leaves. Best thing to do: move the plant out of direct sunlight, loosen the soil, and water less for a few days so it can dry out.
Brown, dried-out leaves on moist soil are often a sign of waterlogging - the roots basically rot and can't absorb water properly, even though there's plenty of it. Try loosening and aerating the top layer of soil so air gets to the roots. How often are you actually watering, and is your hydrangea in direct sun or more in partial shade?
The combination of moist soil and brown, dried-out leaves is tricky because a lot of people just end up watering even more. But in this August heat, it could also be that your hydrangeas are suffering from heat stress - when temperatures get too extreme, they basically shut down, no matter how much water is available. This is especially the case with blue or pink hydrangeas, which are happier in partial shade. Take a look and see if yours are getting direct sunlight, especially at midday?
Still, I'd check your watering first. Even if the top layer of soil looks moist, there could be waterlogging underneath - the roots basically suffocate then. Try it this way: water less often, but when you do, water thoroughly and let the soil dry out a bit between waterings. If the potting soil is really compacted, new drainage holes could help too, so excess water can drain away.
I'm less inclined to think it's pests - that would usually show up with spots or holes first. Try the two measures first: water less frequently but more thoroughly, and see if you can provide some shade (even with a parasol if needed). Within a week you should see some improvement if that's what it was.
Waterlogging is very likely the problem here, but there's one detail that often gets overlooked: in this heat in August, hydrangeas can also suffer from sunscald, especially if they're suddenly getting more direct sun than usual! It looks exactly the same - brown, dried-out leaves with moist soil. Try protecting them a bit from the most intense midday sun with a shade cloth or by repositioning them, and really cut back on watering until the soil dries out on top again. They need less in this season than you'd think!
Your answer
Log into answer.