Yellow Leaves??

I have very poor, sandy dry soil and with all this dry weather, have had to water most of the plants every single day for what seems like ages now. But some of the plants have started to develop yellow leaves, some look like they have developed Chlorosis (Iron deficiency), but others (Including my Ceanthous Sky Lark) have lots of totally yellow leaves, not just the around the veins like Chlorosis. I have really cut back on watering the Sky Lark bush to see if it improves. But to be honest, the ground seemed so dry beneath it, I can't imagine it has had TOO much water, or anything in my garden, because it just runs straight through and dries out really, really quick! The other plants that are getting some yellowing leaves are Pyracantha (I have two and they're both young plants), Hebes and I think the Mock Orange has Chloris too.

Do I need to add Iron Sulphate to the soil???

 

Sally, check out the difference between magnesium deficiency and iron deficiency (chlorosis)
I grow on sandy soil here but is now a deep sandy loam thanks to lots of manure, compost, mushroom compost, etc over the years. It makes a big difference to plants.
I think the problem is due to soil being very dry and the temp being very high. Most of our gardens are feeling the heat of this summer so far.
I would spray with epsom salts in the evening.....it is an excellent conditioner and could address some of the leaf yellowing, esp if yellowing occurs between the veins. A second spray a few days later.
For now, keep watering but consider adding bulky matter as a mulch. A mulch helps conserve whatever moisture is in the soil.

 

Thanks as always, Verdun.

Have to try and find something to use as a mulch!

 

Always best to mulch thickly one or two plants than to spread mulch thinly over a large area Sally. When I plant, I always mulch pretty thickly.....after a good drenching

 

I've noticed that my Clematis has developed brown/ yellow leaves at the base. It is in the raised bed with the Scabious. I keep both hydrated and feed with liquid seaweed now and again. The compost is g/p, mixture of peat based and organic peat free ( aiming to be peat free eventually but difficult to get large bags of peat free g/p compost here ). Could this be magnesium or iron deficiency? The Scabious are doing fantastically well this year, so unaffected. The brown/yellow leaves on the Clematis appeared after storm hector but as it's low down and the Scabious give some protection. I did have to cut off some flowers on the clematis as battered by the storm but otherwise physically it looked unscathed. I'll take a pic later on.

 

No, I think it is simply drying out Lucius. That compost, albeit "hydrated" , does not hold moisture for too long I think. Those older leaves are being jettisoned.....clematis often do this anyway. As long as the new growth is nice n green.
Not to be alarmist lucius, but my feeling is your scabious may well succumb to mildew if the conditions are as dry as I think they are. So, for both plants, I would water very well and then apply a thick mulch. I would also be inclined to apply chicken pellets or dried manure mixed in with the mulch

 

@Verdun I planted the Scabious 4 years ago and the Clematis 3 years ago. I've not had any problems with the Scabious and mildew. I had forgotten, but remembered after reading your post, that I had the same problem last year with the Clematis and the compost had dried out a bit - I should make a gardening diary to record how everything grows, so I can refer back to it.

This is the raised bed. Scabious look a bit floppy as just watered. I had planned to have a burgundy coloured Scabious with the pink, white and lilac ones, but the little pots I bought last autumn didn't make it through the winter - my fault probably.

I did add new compost this spring and some bonemeal. Mulching might present a bit of a problem at the moment but I can do it in the autumn.

 

Its looking good Lucius I cut scabious hard back in summer when flower power is reducing. Quick feed and water and it soon flowers again. I also divide plants in autumn

 

What do you mean cut back hard in summer? I don't cut mine back until Oct/ Nov when they finished flowering. Should I do it when they are still in flower? I didn't realise they could be divided either . I must try doing this. Do you just stick a fork or shovel in or use a knife?

 

Just check regularly for first signs of mildew Lucius....usually the stems develop white covering. Then is a good time to cut back...hard so no leaf is left. Spray with fungicide or at least clear away then water then mulch.
I cut back healthy violas, scabious, some geraniums, etc., in summer when full flush of flower is over and repeat the above for rapid regrowth and flowers for the rest of the summer.
Yes, divide for more plants.....I prefer late summer/early autumn but spring too