Hello,
I'm new to the forum and not a gardener - and am concerned about my hydrangeas. I have four hydrangeas, each in their own window box. Two are blue and two are white with a pink outline to them (I suppose two blue mophead and two white and pink lacecap?). They aren't very big yet, but the two white-pink ones are starting to look sickly - their flowers are brown and they definitely look the worse for wear (and rather ugly though I would only say this out of their earshot). It has been very hot in London, but I have been watering them well. The two blue ones are doing fine, though turning a sort of pinky-grey colour. My neighbour told me that the reason the two white-pink ones are sick is because they don't have enough soil and I should plant them out somewhere. My Mum says that they should be fine in their window boxes at least until next year, maybe they need to be deadheaded or fed. Can anyone help out with a definitive third opinion as to what I should do?
Thank you very much,
Antonia
Hydrangea can grow 5-10 foot high and wide, so a window box is not enough soil to let them take up enough nutrient and water to become the showy blooms you want. If you have the ground space, go ahead and transplant them this fall. They'll probably thank you for the move. Here in Central Carolina, my hydrangea blooms are just about finished, so it might be normal that your blooms are finishing up for the year, especially in their limited space. If the leaves are generally green and healthy, the plant is probably okay. It's not unusual to have some leaves turn brown even dry up in excessive heat. Though you water a lot, the window box is not letting the roots get deep enough to take up enough water. Hydrangea demand tons of water especially if you're experience excessive hot sun and/or dry conditions. By the way, dead-heading will not produce more blooms, but might make the plant look more tidy.
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luis_pr
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I agree with twittel that most hydrangeas get too large for a window box unless you are growing one of the compact Cityline Hydrangea Series or some other compact hydrangea available in the UK.
Browning of blooms can be caused by insufficient water or by a small root system that is not yet capable of getting lots of water to the leaves/blooms unless your water a lot. It helps to keep them well mulched and to water early in the mornings. I recommend watering the soil only from the base of the plants outwards to make sure the root ball and all the small roots get enough moisture.
When they do not get enough water, you normally notice the edges browning first and then the browning continues further inwards. If you correct the soil moisture problem, the browned-out leaves will not change to green but, at least, the browning of the leaves should stop. In future years and as the root system expands, this should not be such a big problem.
But lacecaps blooms are different and that could also account for the early browning out. Lacecap blooms consist of fertile flowers in the middle surrounded by one or two rows of infertile sepal flowers around the rim of the bloom. The true fertile flowers in the center, once pollinated, make the sepals rotate and then brown out to begin the seed producing process. Mopheads do not always do this since their blooms have very few fertile true flowers. So, do not be surprised if you notice lacecap blooms lasting less and browning faster than mophead blooms.
If these four hydrangeas rebloom, feel free to deadhead them often as deadheading [u]does[/u] encourage more blooms but, only in reblooming hydrangeas like Endless Summer, etc.
I share your pain and desire to keep the leaves looking a nice dark green color. We are under a very hot summer with temperatures in 37-46 daily until later this month or early September so hydrangea leaves are suffering all over and looking mostly brown. No rain since May or early June. Whew!
Browning of blooms can be caused by insufficient water or by a small root system that is not yet capable of getting lots of water to the leaves/blooms unless your water a lot. It helps to keep them well mulched and to water early in the mornings. I recommend watering the soil only from the base of the plants outwards to make sure the root ball and all the small roots get enough moisture.
When they do not get enough water, you normally notice the edges browning first and then the browning continues further inwards. If you correct the soil moisture problem, the browned-out leaves will not change to green but, at least, the browning of the leaves should stop. In future years and as the root system expands, this should not be such a big problem.
But lacecaps blooms are different and that could also account for the early browning out. Lacecap blooms consist of fertile flowers in the middle surrounded by one or two rows of infertile sepal flowers around the rim of the bloom. The true fertile flowers in the center, once pollinated, make the sepals rotate and then brown out to begin the seed producing process. Mopheads do not always do this since their blooms have very few fertile true flowers. So, do not be surprised if you notice lacecap blooms lasting less and browning faster than mophead blooms.
If these four hydrangeas rebloom, feel free to deadhead them often as deadheading [u]does[/u] encourage more blooms but, only in reblooming hydrangeas like Endless Summer, etc.
I share your pain and desire to keep the leaves looking a nice dark green color. We are under a very hot summer with temperatures in 37-46 daily until later this month or early September so hydrangea leaves are suffering all over and looking mostly brown. No rain since May or early June. Whew!