Rhodedendrons - Is this Powdery Mildew?
christurns
Posts: 5
Hi, apologies if this information is elsewhere, I'm brand new to gardening and looking for some reassurance.
I planted four rhodedendrons at the start of June in the same bed, and none as looking as healthy as I think they probably should. I'm getting some black marks on them, and some of the leaves are turning yellow and falling off.
The rootball is level with the soil, and the surrounding soil is fairly moist; I don't think its particularly free draining, but I'm not really the best judge at this stage in my gardening career. I've read conflicting information on whether it should be for rhodedendrons?
A quick google suggests this might be Powdery Mildew and waterlogging, but like I said, I'm a complete beginner! Literally, this is the first thing I've ever planted.
If anyone has any ideas of what it is, or things to try, it would be greatly appreciated. I've attached some photos of two of the plants.
I'm in Scotland, surrounded by farmland if it makes any sort of difference.
Thanks,
Chris
Posts
Do you know whether your soil is acidic or alkaline? Rhodo's require acidic soil - they may tolerate neutral pH but not a limey (alkaline) soil. If you don't know, get a cheap soil pH testing kit. If it turns out you have a high pH (alkaline) you could try growing them in large containers using ericaceous (acidic) compost.
Our soil is acidic, and when I planted them, I dug a hole double the size of the rootball and filled the rest of the hole with ericaceous compost aswell.
Your shrubs look like they are suffering leaf spot and it may have spread from one plant to another. If you planted it in June, it's important for any shrub, the first year requires consistent watering, especially the kind of hot spells we have had recently. You should collect rain water and avoid watering from the tap. Promptly collect dead leaves and do not compost it. Also, I recommend you remove the top layer of your soil carefully and lay down a new layer of compost or mulch around the base generously.
Last edited: 10 August 2017 20:58:57
As Christurns is in Scotland he/she will be able to use tap water. I have done so for over forty years.
Yeah, I haven't been watering them that much to be honest. Maybe once a week or so. We've had some fairly damp spells up here in Scotland and I've been worried about them getting waterlogged. Especially as the surrounding soil has remained quite damp.
As Joyce says, I'm up in Scotland, but we've got the added bonus that our water comes directly from a hill, so is just rainwater anyway.
Borderline - Do you think I should remove the top layer of the whole bed (it's about 4m x 1.5m), or just around the shrub itself?
Just around the shrub. Lay a new layer over those areas. No need for the whole area. Water generously if you water once a week. I personally don't think you are doing your shrubs any harm by over watering in the first year. The shrub looks quite big and the larger the shrub, the more problematic for them to settle in.
Cool - thanks very much for your help! I'll get on it first thing tomorrow.
Chris