Box plants going extremely yellow (Buxus plant?) [photos]
Hello.
Around 4 weeks ago I purchased 4 of these plants (Buxus?) from a local market stall. They were all very healthy looking and appeared fine for the first week.
However two of them have since started going yellow at the leaves. I assumed under watered so I've watered them daily (late in the evening). I've also re-potted them.
The only difference between the four plants is, the two that are growing healthy are shaded by the side of the house, while the other two (going yellow) are in direct sunlight (south facing) for ~8hrs a day. Underneath the top layer of leaves it appears green still.
Am I under/over watering? Under/over feeding? Could it be the sun? Or were they dead before I bought them?
Two look like this:

The other two look like this:
14 days ago:

3 days ago:


Any advice and help is appreciated. I've no idea what I'm doing wrong here.
Posts
Hopefully someone who knows better than me will come along in a minute. Firstly, it doesn't look like box blight to me - my suspicions lie with that frost we had a couple of weeks ago, because although some plants are hardy, like my magnolia and my fatsia japonica, that frost
came along and spoiled all the fresh new leaves because they get early morning sun, and it is the effect of the sun melting the frozen cells in new leaf growth and effectively breaking the cells, which causes the problems. Box, like yours, has those little tender light green leaves at this time, which over the summer go darker and toughen up, and become hardier, but it wouldn't surprise me if when they are tender, they could get spoiled by the frost. As you say, the growth beneath looks healthy, and where I can see the backs of your healthy leaves, they don't have any spores on them. I expect someone will suggest you trim off the dead bits and the plant will put on some more new growth very soon. But wait for an expert to write back to you!!
Thanks for your comment. What you say does make sense.
Crikey....another Box problem.
I've said it so many times, I'm starting to bore myself
......don't trim your Box until Derby Day (usually the first week in June)
I agree with BB, it looks like frost damage and they should recover, although the open cuts do leave them open to box blight at a later stage.....as a certain well known TV garden presenter has found.
You've done nothing wrong at all CJ. The people responsible are the people who supplied the market stall holder, after all, they've nothing to lose once they have their money and they do look more saleable when neatly trimmed.
For me, I would live with them for another month when the risk of frost (hopefully) has past, then trim them back to, but not into dark green leaves.
If necessary they can be trimmed again in September, just keep well outside the frost season.
I'm glad someone who knows better than me came along, as it was a case of the blind leading the blind before. Feeling a bit smug that I was probably right about the frost!! I'm getting the hang of this gardening lark.
Thank you both.
Do you suggest I continue to water daily, and keep away from the sun for now?
I watered ours every day when it was sunny last year pretty much, to prevent them drying out. They went a bit bronze over the winter, which is due to nutrient deficiency, so I top dressed with some new compost containing slow release fertiliser a month or so ago, and will give them liquid feed now that the growing season has begun, to try and make them green again. As long as they have the ability to drain easily, can't be any harm keeping the compost damp. Apart from the frost issue, it is probably as well to have them in some sunshine rather than somewhere dank where spores could develop and spread. I don't water in the winter. That is what I would guess anyway.
So what I meant to say was, keep an eye on the weather, and if a frost is possible, drag the pots into a sheltered area - maybe the shady bit where the two bushes that survived are kept. Then return to the sunnier spot when the danger has passed.
Mine get wind-burnt too. They suffer in poor conditions in their pots, and dry out too fast on windy sunny days. Keep them somewhere more sheltered for now.
I have the same problem. I think I read somewhere that the leaves will return to green? I hope not as I have trimmed much of mine back in the hope of salvaging it so I am hoping for some new growth to fill it out again!
Was I correct to remove the dried growth?
Anyone know when it's the right time to trim it please. Before the sun it showed lots of new growth.