How to keep potted shrubs healthy?

Ffoxglove

Hi there, 

I am just posting to ask for advice really. My garden is mainly pots and so I was hoping for some advice on how to keep potted shrubs healthy and moist.
I have everything in pots: from roses, magnolias, hebes azaleas, acers, camellias and more. I water the garden regularly with the hose because it gets dry easily but I wonder if I'm using the best potting mix? 
I've heard of moisture retaining ingredients you can add in. TBH I generally just buy the best soil I can afford at the time of fit in the car to top dress the pots but if anyone has advice as to what they use I would gladly take it!

Thank you in advance!

Obelixx

Water retaining gel is usually used for hanging baskets not pots and you wouldn't want it in the pots over winter cos of all the freezing and expanding and contracting.

Personally, I like loam-based John Innes no 3 type composts for pots with up to a third multi-purpose compost to help with moisture retention.   For permanent plantings in pots you need to feed the pots with a good, slow release fertiliser every spring as the nutrients will all have been used up.   

Some people like to do a top dressing every spring - scrape off the top layer of compost gently to avoid root damage - and replace it with fresh.

You'll need to water the pots by hand as and when needed according to temperatures and the plant and use occasional liquid feeds high in nitrogen for leafy plants or a tomato feed for anything that flowers and or produces fruits or berries.   I find it's quickest to go round my pots with a hose pipe with a spray nozzle so I can also rinse the foliage when it's very hot and dry or there's been a dust storm of some sort. 

Ffoxglove

Thanks @Obelixx! 

I’ve got Top rose and I use tomorite too. I have some Ericacious granules too but what nitrogen rich feed would you suggest. 

I have to admit some of my pots are just multi purpose compost 😬
Which is probably why the plants are less than impressed but as I pot things on to bigger pots I want to get it right! 

Do you use a particular multipurpose? I’ve used jacks magic before...

Obelixx

Any mpc I think as you want it for the fibrous properties.   It's a long time since I've bought composts and feeds in the UK so I can't help with brands so you'll have to check labels for feed content.

You need to look at ratios of N for nitrogen for leafy plants and plenty of P phosphorus and K potash for fruit and flowers plus some magnesium and other trace elements for all round plant health.  Liquid seaweed fertiliser is a good all round plant and soil health booster if you don't want to have all sorts of different packets and bottles to store.

Ffoxglove

Thank you for advising me! I appreciate you taking the time. 

Obelixx

Hope it works for you.  I have loads of pots too, some permanent and some while plants grow on or wait for their new home to be ready in this new, to us, garden.  Watering can take a while in the height of summer.

Cambridgerose12

I agree with @Obelixx—the only plants I’ve kept happily in containers for several years have been those in soil-based compost. John Innes is good. Obviously you’d want the ericaceous kind for your lime-haters, and that can be tricky to find for some reason—the best bet is often eBay. For fertiliser, I couple regular feeds with granulated organic chicken manure with watering cans of seaweed plus chelated iron. It seems to go down well in terms of plant vigour and growth, although one of my camellias is large enough to struggle now despite regular top dressing and feeding.

learnhow2salsa

Hi,
Can anybody give me any advice about my camellias, please?

I've kept them successfully in very large pots with ericaceous compost in them for many years, watered them mainly from the mains (hard water) but, when I can, using rainwater. It was very hot last spring and summer and I had to water them with tap water a great deal; they also got quite a lot of sun, as my new garden has no shade.
They developed what I assumed was a bit of scorch on their leaves, but this year those in pots and those I planted out in my sandy, but neutral, soil (with some ericaceous compost around them) have turned quite yellow and developed other marks on the leaves. One looks like sooty mould but isn't (because I cannot brush it off).

Any help would be much appreciated.

Tania

Obelixx

Hello @learnhow2salsa.   It's a good idea to start your own thread with an appropriate title so you get answers form the specialists on here, rather than piggy backing on another more general thread.

Here goes tho.   Ericaceous plants like camellias cannot take up iron and magnesium when there is calcium present in the soil or water and that makes their foliage go yellow and unable to feed the plant properly via photosynthesis.   If you have to use tap water you need to correct it with a liquid feed containing sequestered or chelated iron - easily available in GCs and many DIY stores with garden sections.

Magnesium deficiency can also be fixed with a foliar feed of Epsom salts - 15ml of salts diluted in 5l of water and poured or sprayed on the leaves.

Camellias, rhododendrons and azaleas set their flower buds from mid to late summer - monsoon season in their natural origins - so need plenty op water all thru this period and into early autumn or they will drop their buds to save energy.   If you must keep them in pots you need to water daily and generously especially in hot dry spells at any time of year.    They would do better in the ground tho if you can plant them out - unless you have alkaline soil.

learnhow2salsa

Thank you for your advice regarding both the camellias and the new thread, Obelixx. It is true that I didn't use anything to counteract the magnesium deficiency or the tap water. I will get some Epsom salts and special feed with iron as you advise. Once they are feeling happier, I'm sure they will shrug off whatever disease they seem to have.
They have all flowered well though - some of them for the first time. I clearly gave them adequate water, even it if was 'toxic' to their leaves!
Tania

SueAtoo

Have I heard Monty talking about "Feeding Friday" for his pots? I believe he uses dilute seaweed liquid, presumably very dilute if he's doing it weekly rather than monthly/6 weekly.