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16 messages
05/05/2013 at 18:03
http://s4.gardenersworld.com/uploads/images/original/23119.jpg?width=352&height=250&mode=max

 


Can anyone tell me what is damaging the leaves on this evergreen Rhododendron

 

05/05/2013 at 18:11

http://s4.gardenersworld.com/uploads/images/original/23120.jpg?width=273&height=350&mode=max

This is a closer look at the Rhododendron

 

clk
06/05/2013 at 17:34

Hi spring jean, is it merely discolouration? It's quite difficult to see on your photo. If so, it might be lacking nutrients, either because the rain's washed them away or because it's not compatible with the soil/compost it's in. According to the RHS plant finder website, they like 'moist, humus-rich, acid soil but will not tolerate deep planting'. So, in pots they usually need to be in ericacious compost. And does it need potting on in fresh compost and a slightly bigger pot?

clk
06/05/2013 at 20:16

Give it a dose of sequestrene. It won't turn the current leaves darker green but new growth should be a lot healthier. If you live in a hard water area use rain  water when possible or else retreat with sequestrene every 8 weeks through to autumn.

06/05/2013 at 20:47

And be careful with the mulching.  Mulches must not be too thick or roots will be deprived of air

clk
06/05/2013 at 20:55

So, when the leaves are yellow on any plant will sequestrene help? I have a few plants that have yellowy leaves (including a digitalis) and I think it's due to all the rain washing the nutrients away (the digitalis that were in other drier places look healthy). I was going to scatter blood fish and bone around but is that inadvisable?

clk
06/05/2013 at 21:12

Yellowing (Chlorosis) is due to lack ofnutrients . this can be because the soil or compost is short of nutrients, or because of waterlogging which can prevent nutrient uptake, or, in the case of acid loving plants, it can be because the soil is alkaline, which stops the roots from absorbing the nutrients. Sequestrene contains nutrients in sequestered form, which is techie for a form allowing them to pass into the roots. Basic sequestrene only has sequestered iron, the main cause of chlorosis. Sequestrene + has a lot more nutrients in this form. 

Digitalis is OK in alkaline soil so use something like miraclegro for a quick pick me up.

 

clk
06/05/2013 at 21:35

Oh blast, I just bought the basic sequestrene online and now wonder if I should have bought the +. However, it won't go to waste - a friend has a magnolia with the same problem as the rhododendron so I can give it to him. But that's great about the miraclegro idea for the digitalis - I'll do that, thanks.

clk
07/05/2013 at 19:30

I was given this as a gift last spring in a pot, I planted it in this big tub soon after also using ericacious compost. I wondered if I fed it with  plant feed ericacious that might help

07/05/2013 at 19:40

Are you in a hard water area?

07/05/2013 at 20:23

Ericacious feed should help, in a pot it will need feeding anyway. Rain water is best for watering. Every year you should scrape away a bit of the top compost and give it some new ericacious compost. I think it looks hungry.

08/05/2013 at 23:50

Hi, some excellent advise on here there's just a couple of  other things rhodies can get sun  burn so don't keep it in the sun all day and make sure it doesn't get waterlogged and don't let it dry out. It's a good idea to stand the pot on a couple of bricks to be sure it can drain efectively

09/05/2013 at 13:10

Rhododendrons don't need much fertilizer. Soluble fertilizers don't last long. so for rhodies in pots  it's a good idea to add some slow release pellets, with an occasional Sequestrene+ feed to deal with the acid side of things if you can't provide rain water.

09/05/2013 at 14:38

Have you got it in lime free soil?

 

20/05/2013 at 19:35

our water isn't really that hard, but I mainly use rainwater for the Rhododendron. It is planted in Ericacious compost.

The yellow leaves come off easily when touched, will these be replaced by the plant?

20/05/2013 at 20:31

Just beneath the flower truss you should see some buds. Once the flower is finished the buds should fatten up. Help them by removing the flower at that point to stop energy going into seed production. If the buds don't develop then it suggests something serious like vine weevil grubs. If you have any vine weevil killer you might want to treat it now just in case. Or you might lift it out of its pot for a quick inspection for grubs, drainage etc..

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