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Dahlia Issues

Alfie_Alfie_ Posts: 456
in Plants
Hi,

I have an issue with one potted dahlia and also my dahlia border I have and would appreciate any insights offered.

The potted dahlia was doing so well with so many flowers and every leaf was really nice and green:



This was a few weeks ago and now the flowering is not as great and so many leaves have turned yellow:


The only thing I can think of is that it has grown very bush and is very wide compared to the pot so maybe the pot isn’t big enough to support it now. I treat all my dahlias the same over the summer which is regular watering and feeding once a week. The ratio of fertiliser is 12-12-36 and says it supports flowering so no idea why all my dahlias have so much foliage. This is the fertiliser I use - https://www.richardjacksonsgarden.co.uk/shop/planting-feeding/flower-power-premium-plant-food/?attribute_size=1.5kg&gclid=Cj0KCQjwr4eYBhDrARIsANPywChwpeixXTR8lOzPMBN8fyDOeV7Z37AsfoG6vGKK08h806Krg15Q0ygaAjSCEALw_wcB

looking at previous post maybe it’s best to stick with just tomato feed?

Here are the border dahlias which have no health issues and do look nice but here is way too much foliage so a lot of the flowers get hidden:





I would say half the orange ones I covered up. The dinner plates on the end have a few hidden quite deep in the foliage. Can I just cut a load of the foliage off to better reveal them? 

Thanks in advance for any guidance offered. 
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Posts

  • PlantmindedPlantminded Posts: 3,580
    This looks like possible overfeeding - your plants are producing leaf growth at the expense of flowering.  The food you have been using looks strong compared to the NPK ratio of typical tomato food which is: 4:3:8, weighted to encourage flowering.  You could either stop using any feed to allow your plants to regain a normal balance or try repotting them in larger pots with fresh compost and change your feeding regime.  Removing foliage from your other plants to reveal the flowers won't harm them but try to retain a natural look!




    Wirral. Sandy, free draining soil.


  • Joyce GoldenlilyJoyce Goldenlily Posts: 2,933
    Have you checked to see if there is an ant's nest in the bottom of the pot. I have had several nests this year, far more than usual. Ants like the hot dry conditions we have been experiencing.
  • didywdidyw Posts: 3,573
    edited August 2022
    Mine in pots are more foliage than flowers too.  I have been feeding them with Tomorite.  I was hoping for a really good display this year - lots of sunshine and keeping them fed and watered throughout.  
    Edited to add: those in your border look gorgeous together @Alfie_
    Gardening in East Suffolk on dry sandy soil.
  • Alfie_Alfie_ Posts: 456
    Joyce Goldenlily said:
    Have you checked to see if there is an ant's nest in the bottom of the pot. I have had several nests this year, far more than usual. Ants like the hot dry conditions we have been experiencing.
    No good idea. In the border I had some real ant issues at the start of the summer 🙄 Everyone is always talking about slugs and dahlias but ants are the problem here quite often 😂
  • Alfie_Alfie_ Posts: 456
    Plantminded said:
    This looks like possible overfeeding - your plants are producing leaf growth at the expense of flowering.  The food you have been using looks strong compared to the NPK ratio of typical tomato food which is: 4:3:8, weighted to encourage flowering.  You could either stop using any feed to allow your plants to regain a normal balance or try repotting them in larger pots with fresh compost and change your feeding regime.  Removing foliage from your other plants to reveal the flowers won't harm them but try to retain a natural look!




    Thanks. For the potted one will the yellow leaves possibly recover or should I remove them? 
  • FireFire Posts: 19,096
    I lay off the feeding of that plant for a while and see if it recovers.
    Beautiful dahlias!
  • Alfie_Alfie_ Posts: 456
    Hi people,

    Just reporting back after switching to tomato feed once a week for the dahlias in the beds. Still a few issues. The purple Thomas Edison is still much the same - some great blooms but only 2-3 at a time despite huge numbers of buds? I have attached an image from the website of that dahlia and I wanted it to look more like that; here they seem to have tons of blooms.

    Also, I purchased this dahlia along with the orange one (not sure of the name) and the Spartacus as shown in the picture on the 18th May as pinched out potted dahlias with about a foot of bushy growth. Any ideas why the Spartacus has only just produced its first signs of opening a bud 3 and a half months? So still not one opened flower yet! Same bed, same care, same place of purchase and same stage at purchase as the orange one (don’t know the name) and Thomas Edison. 

    Thanks for any advice

     This dark purple/red bud is Spartacus and is the first one bud to open since mid May:

    Here’s a shot of all three showing it has good healthy bushy growth like the other but no flowers:


    Thomas Edison does have some lovely blooms and has reached over 5 feet tall but there’s always only a handful
    of flowers some of which are hidden despite their being so many buds:



    I wanted it to look more like the picture 😂:


  • FireFire Posts: 19,096
    edited September 2022



    I would say you may have too much planted in a small trough. The root ball on your large dahlia will be big, and in competition with the smaller plants. Keep watering large buckets every day. With your wooden trough, is it sited onto paving or is there earth going down under it? If it's on a hard surface, the trough is quite shallow for big dahlias and the trough isn't full of soil. I've recently topped my pots up with good manure - to offer extra richness and as a mulch to keep the water in.

    Having said that, your plants and blooms are looking good. Your final picture looks like it may have come from a catalogue.
  • Alfie_Alfie_ Posts: 456
    Fire said:



    I would say you may have too much planted in a small trough. The root ball on your large dahlia will be big, and in competition with the smaller plants. Keep watering large buckets every day. With your wooden trough, is it sited onto paving or is there earth going down under it? If it's on a hard surface, the trough is quite shallow for big dahlias and the trough isn't full of soil. I've recently topped my pots up with good manure - to offer extra richness and as a mulch to keep the water in.

    Having said that, your plants and blooms are looking good. Your final picture looks like it may have come from a catalogue.
    Yeh good point. At first I thought that wouldn’t be an issue as we have a large grape vine and fairly large butterfly bush further round that bed which would need a lots of room to grow this big: 



    However, only just noticed it’s wider where these are (95cm) and only 65cm along the dahlia bit. The height of the sleepers is 30cm but the soil is about 8cm lower that the top of them. I think the beds are earth underneath - the paving is just around it. Next year if I spaced them more spread out but in the same bit would they do better? Or is the depth of the bed an issue? It catches a lot of sun there which is why I put them there. Thanks 
  • FireFire Posts: 19,096
    I think a lot would depend if the roots can go down under the bed. I suspect a grape vine would have to have depth to get that big. It's probably worth digging down and finding what's under there. If it's on clay I'm not sure big dahlias will do that well, against competition as well. I would probably stick to lower growing ones. If you took out the buddleia you would have more space to play with.
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