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Large dahlia advice wanted for first time grower

soulboysoulboy Posts: 429

Hi, I'm growing a couple of tall dahlias for the first time (cactus tsuki yori no shisha). I'm a bit nervous regarding the advice I've read in researching how to grow them successfully. A lot of the advice I've come across seems to be geared to show plants and cut flowers and talks about nipping out the centre of the main shoot, taking off lateral shoots and disbudding, and only allowing 4-5 main shoots develop.

The two plants I have are growing at very different rates because, I believe, one was in the shade of a hollyhock, which I've now sacrificed to give the dahlia a better chance of reaching full growth. I've included some pic's of the larger plant, which has now reached about 18". I've read that that is about the height that one should nip out the top of the central stem.

As you can see from the pic's I have two large main stems and two just coming out of the ground. I would really appreciate any advice on how to get the best from these plants. I'm not interested in show flowers, cut flowers or having the largest flowers, so should I just leave it to grow naturally?



  • GardenmaidenGardenmaiden Posts: 1,126


    they look very healthy plants. We are in our second year of growing Dahlias. We have ours in 10 inch diameter pots and have these in a large tray that we keep topped up with water. The surface is covered in little clay rocks (just something my husband had lying around) and the plants are in sun for most of the day. We don't do anything special, we just leave the plants to get on with it. I do pick off the dead flowers so we continue to get flowers.

    Once they get frosted we cut the foliage off and take them out of the pot to dry off over winter. You can leave them in and just cover with alot of mulch to protect the crown (I haven't done this, just read that you can).

    I'm hoping to add to what I have next year.

    I'm no expert, I would deadhead when necessary but not sure about feeding them anything special.

  • PerkiPerki Posts: 2,497

    Hi , you dont have to do anything special for dahlias,  unless they are show plants . I planted one of my larger dahlias quite a bit ago now, its got one flower on and it looks great. I haven't done a thing, just planted it in the ground with some multi -compost and its off. I feed it yesterday with a high potash feed but only cause i was feeding the delphinium next to it ( hoping for a 2nd flushimage).  I probably feed them again throughout the year with a high potash feed to encourage flowering. They can be a bit greed dahlias, pinch the top out to make them more bushy but i just leave mine.

    The tall variety usually need staking , dont forget to dead head aswell 

    After first frost i cut them down to about 6 inch - bring them inside turn them upside down and let them dry - then store them in sharp sand for next year. 


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