Growing dahlias – everything you need to know about how to choose and grow dahlias

Growing dahlias – everything you need to know about how to choose and grow dahlias


Hi there, it’s Alexandra from the middle
sized garden YouTube channel and blog and I’m here at the beautiful Salutation
Hotel & Gardens in Kent to find out all about how to grow dahlias. Steven Edney head
gardener at The Salutation has grown dahlias all his life and his family grow
dahlias professionally, so he’s going to tell us everything you need to know so
that you can have beautiful dahlias like the ones you see here. Now which
dahlias should you grow? Is it just a question of thinking ‘oh I like that
flower’ or what else do you have to think about? I’ve got to be
honest – I think you should grow a dahlia just because you love the look of it,
first and foremost. If you’re thinking about wildlife, then the singles and the
semi doubles – any dahlia where the eye is exposed to insects so they can come in
and land and feed on the nectar – well that’s great for wildlife, but if you’re
looking to cut the flower and use it in some way in the home, then the decorative
types are much better for that. Which particular dahlias do you think are the
best for cut flowers? For me the cactus types. I’ll always
have a soft spot for cactus dahlias because I think they cut really well. I
think they look very good in a vase amongst other flowers, because there’s
nothing quite like them if you’re looking for something a bit softer, then
the informal decoratives are probably the next best choice for me, but then the
‘dinner plates’ of course dominate any arrangement. You can almost just use them
by themselves with a bit of foliage and they’re amazing. Just bask in
their glory – because they’re just so incredible. There are 14 different flower types or styles of
flower on it on dahlias and it’s really only the singles that aren’t very good
for cutting -unfortunately because they’re so good as garden plants. If
you’re looking to cut dahlias, choose any of the other flower types – but not the singles. Can dahlias grow in pots? Yes! Dahlias
actually can be really successful in pots.
The bigger the Dahlia, the bigger the pots – that is not just
because it stops them from drying out quite so much, but also stability. If
you’re growing a big Dahlia, you want a hefty pot so it doesn’t keep toppling
over in the wind. Can Dahlias be grown indoors? Oh now, that’s an interesting
question – I’ve never been asked before. As long as the light levels are really good –
so in conservatories, but dahlias wouldn’t be a house plant –
no – the light level is just too low. Next question – can dahlias grow
in shade or do they need full sun? Some varieties are better at coping in
the shade than others, so for instance I always try growing some dahlias each year
in the shade – maybe just two or three varieties. This year I’ve grown
Purple City, a dahlia called Louise and Louise and one called Yellow Hammer.
Yellow Hammer has been surprisingly tolerant of the shade and
the other two actually haven’t done very well. So do dahlias need a lot of
water? If you’re growing exhibition dahlias, you have to think about the
flower size – really it’s not so much about the plant – it’s actually about the
flower – it’s a huge commitment on behalf of the plant to create a flower the size
of a dinner plate. So those sorts of dahlias require vast amounts of water.
Really the smaller the dahlias and those with smaller the flowers, such as the
singles and the semi doubles or dahlias under a metre tall or around a
metre tall – they’re often much more drought tolerant, and certainly here at The
Salutation, we’re on a light silty soil. We don’t regularly water plants – I wait
until plants are are getting desperate for some water before I would water them,
so it means that some of our dahlias do do better than others and we have to
pick the damper spots for the dahlias that like plenty of moisture. And is that the
same for fertilizer? Like all plants if you if you treat them very very kindly
and give them lots of food they’ll respond by putting on masses of growth
and loads of flowers. But we don’t artificially
fertilize any of our dahlias and so perhaps my flowers are a little smaller
or perhaps I have a few less of them, but it makes me feel uncomfortable at what
many growers are prepared to do at the sacrifice of other environmental factors.
So when do you plant dahlias out? Traditionally it’s always after the risk
of frost has passed and really here in southern England, that is second third
week of May – even as late as the beginning of June. Lots of people don’t
begin to plant out until then. They’re usually growing them in pots already. Start them off in pots in early spring so they are growing. So in May you’re actually planting
a pot plant that’s full of foliage already, but don’t risk putting
dahlias out into the garden until after the frosts – down here, it’s the second week of May right
up until perhaps the end of June when you can plant dahlias. We chance our arm a little
bit in some of our very sheltered corners and plant out as early as the
middle of April and a couple of times we’ve been caught out by that and we’ve
had to fleece some of the dahlias to stop them getting frost. And how do you plant
dahlias once you’re planting them in the ground? I don’t like to add manures or
enrich the hole that they’re being planted into, so we just plant into
hopefully a good garden soil that you already have. Perhaps if you haven’t got
good garden soil, you’d think about soil improving before you reach the point
where you’d be planting out dahlias. We always water them in really well
we almost puddle them in to their holes and because we’re here on this eastern
tip and we have this light silty soil we actually plant into a slight hollow so
that water sits in with the dahlia. Now if you’re on a heavier soil or a clay soil,
you may want to do the exact opposite and actually plant them on a slight
mound so the water runs away from the crown, because it’s all about either
holding moisture or losing moisture from around the new shoots forming in the
tuber. Once planted, we water heavily for that first time and then we mulch and then we
leave them to get on with it and don’t check on them again for at least another
week. So you dig a hole the size of the roots
that you’ve got of this pot plant, you put the plant straight in and you
give it a really good water, you add a layer of mulch around it – something like
compost or well rotted manure. Yes, any garden compost – not multi-purpose compost
that you buy from the garden centers – I often hear people saying about putting
compost around plants as a mulch and I worry that that most gardeners would see
that as oh I’ve got a bag of multi-purpose maybe peat based compost
I’ll put that around my plants. That’s something to avoid – use
organic garden compost or manure of some kind. How do you keep your dahlias as
overwinter? Because we’re on a light silty soil, we can actually very
successfully overwinter our dahlias in the ground so if you’re thinking about
doing that have a little think about your soil through the winter. Do you
have standing water that that won’t drain away very easily or does it drain
really quickly after heavy rain? if the answer is that it’s
draining really freely and that water doesn’t sit on the surface of your soil
then I think it’s always worth trying to leave some dahlias in because it’s one
of the things that puts people off about growing dahlias is that they worry that
there’s going to be a lot of lifting and moving and storing and I always say to
people if they’re prepared to take the risk give it a try because eight years
out of 10 we have no problem whatsoever leaving our dahlias in the ground – the
heavier and colder the soil, the more risk you have of losing those dahlias so
if you’re on a heavy cold wet clay soil then you should lift the tuber. We’ll
cut the foliage back first to a just a couple of inches off the ground,
fork up the tuber being careful not to damage the tubers, and then we’ll gently
dry them. Now people do say about tipping their dahlias upside down so that any
liquid in the stems can drain out and so it doesn’t rot the tubers. You know I’ve
been growing dahlias for 25 years now and my experience has been that people tend
to leave them just tipped upside down and then just forget about them
then come back to them in the spring and all the new shoots that have
formed are facing the wrong way up. We actually only tip our dahlias upside down overnight just to
let any actual liquid come out of the stems
but in terms of the kind of juice in the stems that’ll naturally just dry out
during the winter. Then we turn them right way up. Yyou can store them in crates or
boxes as long as there’s a decent airflow. We actually use our old spent
multi-purpose compost from plants that have died – obviously if they’ve died from something a bit nasty then we wouldn’t be using that compost because
you don’t want to contaminate your tubers with anything, but you could use
sand or straw as well. They need to be in the dark
and they want to be just frost free so they could go under a bench in a
greenhouse and be covered, or a cold frame or they could go into a shed
or a garage if you don’t have a greenhouse and and they’ll be completely
dormant and quite happy there all winter until you remove them in the spring and
kickstart them into growth. And how do you deal with dahlias and slugs and
snails? Oh that’s got to be the number one ask question because dahlias are
absolute martyrs to slugs and snails. I think the big picture is very
important – how holistically how you manage your garden, no matter how big or how
small, and it’s really important to make sure you’re attracting wildlife into
your garden and that the birds are helping to control populations of slugs
and snails. It’s not about eradication – it’s always
about controlling populations to a tolerable level, so for us what we can
physically do is to surround the dahlias with sheep’s wool and we also use the
organic slug pellets. Now the difference between the old slug pellets and the new
ones is that the new slug pellets are baited with a pheromone and they
have ferric phosphate in them so it’s like an iron tablet so it
causes no harm to invertebrates or birds if they then pick up the mollusc and eat
it – it won’t do them any harm but they do have to get wet
to activate the pheromone whereas the old slug pellets – they always used to say
don’t get them wet because that lowers their effectiveness. So people are often
come to me saying the new slug pellets aren’t working and I explain that if they
put them down and it didn’t rain or get plenty of moisture like a morning dew
within 24 hours, they need to water them so that it activates the pheromone and attracts the
slugs and snails to them. Nothing is the Silver Bullet
– it’s very much to do with the wider garden and and how
you’re managing it and encouraging wildlife into your garden to help
control those population levels – newts frogs, hedgehogs, birds – all of these will
be helping to control your population levels. What plants do dahlias grow well
with? What would you plant with them in a border? Well of course dahlias
have that exotic look to them so I always love combining them
with cannas and if you’re going to grow the larger
decorative types or the dinner plates they want very similar conditions and
similar moisture levels, so often I think about plants as in combination, as it as
a small community and so I’d combine plants with other plants that like
similar conditions, so I don’t have to keep trying to give different plants
different things. So exotics are always high on my list to go with dahlias
because I think they go together like peas and carrots. Miscanthus too works well and I think dahlias
work really well with grasses just because I love the position that a
Dahlia plays you know with its incredible flamboyance against the
subtlety of perhaps a fine grass. Salvias of course because they’re a late summer
flowering plant and they’re also what they call a ‘short day plant’ so as the
days begin to shorten in length the flowering intensifies and so if you
pick plants which also have that same attribute like salvia and miscanthus then they create a combination together that really zings
rather than thinking of them in isolation. And do you have any other
advice for people thinking about growing dahlias? Yes don’t overwater them in the
spring. Very often people will plant tubers – whether it be in a pot to start
them off or whether it be planting the tuber straight into the ground – what
people often do is water too much too early. The demand for water for most
plants doesn’t come until the high summer – imagine the plant and you have to
start thinking like a plant. It’s not three inches tall – suddenly it’s three
feet tall and all of the leaves are spread all over the plant and the plant
is trying to pump water to all of those leaves during the high summer which is
at its hottest point. So save the watering – do more weeding early and water
a little later in the summer. There are links in the description below to the
Salutation Hotel & Gardens and other resources and if you’ve enjoyed this please do hit
‘like’ and then I’ll know you’d like to hear more about growing individual
plants in your garden, and if you have a middle-sized garden or a small garden
and you don’t have enough time, you don’t sometimes have enough expertise or you
don’t have enough money and you want it to look absolutely gorgeous, then
subscribe to the Middlesized Garden YouTube channel for tips ideas and
inspiration for your garden – thank you for watching goodbye

52 thoughts on “Growing dahlias – everything you need to know about how to choose and grow dahlias

  1. What about the dreaded mildew? Mine often come down with it at the end of the season. Also, dahlias are so easy to grow from seed. My seed grown dahlias are proving more resistant to mildew than those I've grown from tubers.

  2. Thank you alot. I just grew my first.dahlia…not too successfully by his standard but in my area it really was….and desperate for WATER..lol..in my area they always are.

  3. And now I must cross the pond between us and visit Salutation! This year has been inhospitable for the dahlias I planted out. Too much of every condition – wind, rain, cool temps, pests, hail, etc. But I will try again next year! Thanks for the beautiful and informative episode. 😊

  4. Me encantan estos vídeos. Aunque sólo los puedo ver ya que no entiendo inglés. Me di cuenta en este vídeo que lo escrito se me facilita .Hermosas dalias!! Saludos desde Argentina! !!!!

  5. Thank you Alexandra, really enjoyed this video, Beautiful house and garden and advice. I have just planted three 'Bishop' foliage dahlias. Unfortunately too windy for the taller types but I like the singles for the pollinators.

  6. Thank you. Very interesting and informative …. I always thought of Dahlias needing feeding a lot. I have used tomato feed (liquid ) on them. Dalefoot composts for mulching or growing in pots are absolutely brilliant …. made of sheep’s wool and bracken … very green!!

  7. Excellent interview. You anticipated a lot of our questions.
    I have single petaled pink dahlias 🌸 and a burgundy & white dinnerplate dahlia quite stunning. Dahlias certainly can hold their own in any border. I like the suggestion of planting them with tropicals and grasses. Take care! 🌿

  8. This has come at a great time Alexandra. Just about to plant out dahlias here. Fantastic tips and advice. Thank you. Anita

  9. I love dahlias and currently have 61 different varieties growing on my allotment in the south of England. A very informative video full of questions that everyone would like to ask. Your channel is super and so inspiring for beginners to the more experienced gardener. I just wish someone would produce a scented dahlia. Looking forward to more of these videos. One on roses, lupins, sweet peas and cosmos would be my choices. Thanks again 😍🇬🇧

  10. Great video… thank you so very very much what an inspirational Garden. Now I want to plant dahlias I've never been real successful with them I want one of everyone

  11. Very nice and interesting,I live in the north of Italy and have the same problem often.I buy Dahlias that shoud grow 70/80 cms and then maybe 1,20 meters and others 1,20 and then 1,80 2,0 meters.What is wrong?

  12. Excellent video, I love growing glads with my dahlias. They support one another and look beautiful together in a cut flower arrangement

  13. Would it be possible to do a feature on growing dahlias for the local shows, covering things like "stopping", "disbudding" and deciding how many stems to allow on a plant? Like all of your videos.

  14. Very knowledgeable man and his easy going style was lovely to watch. Despite depending on tank water in rural Australia, I am going to give dahlias a go this year. The huge variety is so enticing. Thanks for posting.

  15. Really great video and very pleasant man to listen to. Very heartening to hear his holistic approach to gardening also. It's the way it should be.

  16. Thank you for the video. Great professional advice. One more question though, please. Earwigs damage my dahlias and not only. Is there a way to get rid of them?

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