Recently planted shrubs diseased

About 9 weeks ago we had our new garden landscaped and loads of large shrubs added. Things looked great until the last couple of weeks since when 3 of the varieties have developed a problem. They are Cornus alba Sibirica, Sambucus Sutherland Gold and Mahonia japonica. There are 3 plants of each type and all have the problem. The leaves are withering and dying on the new growth. I've put images in a gallery album Album: Sickly plants! One example shown here.
The garden is heavy clay. I've been watering the new shrubs every 4 days, about 40secs-1 minute per plant, as instructed by the gardener.

Any ideas anyone?

Thanks

 

Cant help thinking that although you are watering, the rootball has dried out and not being totally wetted.
Difficult to say though.
Were the plants pot grown or bare rooted?

 

Thanks for the reply. The plants are all pot grown. The watering technique I'm using is to water over the rootball, 10-20 secs per plant, doing 3 or 4 plants at a time in rotation, 3 or 4 times per plant. This is so the water has time to sink in. That's the theory, anyway.

 

I would put a whole watering can of water on each shrub at this time of year.

 

I hope not, they were large (expensive!)plants from a bona fide nursery and the planting was carried out by a landscaping company with a good reputation. The Cornus, for example was described on the order list as "125/150 CG36" which I believe relates to the size.

So that kind of damage can be caused by drying out? I thought the whole plant wilted when it was getting dry?

 

I'm watering with a hosepipe. Is it better with a watering can? Sounds like it may be.

 

I'd be inclined to use one watering can per plant, say 2 gallons, and add one or two drops of washing up liquid to the water.
I'm thinking if grown in peat based compost, the rootball has dried out and once totally dry it can be difficult to wet.

The washing up liquid will work as a wetting agent.

 

Hmm, I grow both Sutherland's Gold and the Mahonia. Have you had any very strong winds prior to the problems? might be that the leaves have got wind scorch. Have you been watering with the hose sprinkling during strong sunlight another possible cause of scorch. The other much worse scenario is that if it's a brand new garden the builders may have compacted the heavy clay you say you have and the plants are struggling to get through it. Often, unfortunately, landscaping companies mask big, time consuming problems by covering them up with compost when planting. It is not until the plants grow out of the compost that problems arise. If you haven't had strong winds prior to things not looking so good or watering in hot sunshine I would contact the landscaping people and ask them to come and look at your concerns. Certainly I agree with Zilly and Pete 1 good watering is better than little and often which will attract the roots of your shrubs to come to the surface which is exactly what you don't want.

 

Thanks for these replies. We have had some very strong winds, and it's a windy spot anyhow. Re the watering I'm using a hose and pointing at the base of the stems. The beds are quite big so I'd be walking on them to use a watering can, and it'd take an age - there are 46 plants in all

Here are 3 photos of the worst affected Cornus. I still find it hard to believe that this damage is watering, it looks so much like a pest or disease to my inexperienced eye. (it's worse than those photos make it look)


Silu: The beds were cut around the time of the heavy rains in Spring, they were rotavated and left for a couple of weeks to dry and rotavated again prior to planting. Then about 2 to 3" of mulch/soil improver was put down. There isn't much soil above the clay here, it seems to vary across the garden, but stuff does seem to eventually grow as the show house next door has plenty stuff in their garden.

The guy from the landscaping is coming round next week hopefully, in the meantime I've given stuff a watering with the hose (in the rain ).

 

Certainly my Dogwoods are in tatters after the dreadful gales we had a couple of days ago. I have 4 different ones. The ones with yellow leaves and red stems are the worst swiftly followed by ones with just plain green leaves and stems. Mine were looking absolutely fine and now look way worse than in your photos so maybe it might be wind scorch. Hope the landscaper can give you the definitive answer.

 

Thank you all for your replies, will keep the thread updated if I find out anything.

 

The nursery (Wykeham Mature Plants) agree with you guys, wind burn from the recent gales and lack of water. I've upped the watering regime to stick twice as much on and told the wind to stop.

 

Thanks for the update @John Dalrymple Good luck with getting the damned wind to stop. I have failed miserably on that front! I don't know where you have the Sambucas planted but mine do much better in shade and a wee bit of shelter (I have 1 original a la below and 4 "babies" (cuttings) from it. It is such a lovely foliage plant but I lost 2 of the babies last Spring due to late frosts damaging all the new growth. It isn't perhaps quite as tough as people imagine.
If yours are all in sun and you have a shadier/more sheltered spot I would amybe move it/them in the Autumn after leaf drop.
When watering I'll leave the hose on a certain spot for a good while so the ground is really wet and then that should be enough not to have to water daily. Lots seldom is much better than little and often. Hope you enjoy your new garden I am sure you will once things settle down.

 

@John Dalrymple Go Google "twig blight".