I just ordered some dahlia tubers (see the end of this article for what I bought and why). Up to now I have never needed to grow them because I can go to the market and get the cut flowers to photograph. But the appeal of growing dahlias – despite or because of the supposed difficulties – has grown more and more. But, importantly, I want to grow the kind of dahlias that attract bees and other pollinators. Again, see the end of this article for more about that.
Just to mention that the flower of the ‘big bloom’ kind that I like most is the peony. So dahlias are not the bees’ knees for me. And of course, chrysanthemums, like this one – a chrysanthemum greeting card showing the beauty of the colours and arrangement of its petals are similar to dahlias. Click the image if you are interested in grabbing this card for yourself.
And if you are not sure whether a particular plants is a chrysanthemums or a dahlia, then take a look at this article where I start with the name. You will read that the dahlia was named in honour of Andreas Dahl (1751–89), a Swedish botanist.
While I have never grown dahlias, I am interested to know how to grow them. (More about that later.) And this is what I have gathered from my researches. In the UK, dahlias will flower from the height of summer through to almost the end of the year in the right conditions. That means keeping them safe from frost. A hard frost will kill the tuber underground, and a light frost will shrivel the plant above ground. So with a risk of frost, cut back the foliage to about a hand’s width. Then dig up the tubers and hang them upside down for a day to drain any liquid out of the stems.
If you don’t, then the liquid will encourage the tuber to rot. With that job done, keep the dahlia tubers in the dark in an unheated conservatory or greenhouse.
Leaving Dahlias In The Ground Over Winter
If you don’t have anywhere to store dahlia tubers over winter, then you can leave them in the ground. You can only do that, however, if the soil is well drained. And if the soil is well drained, then you can protect them from frost by covering them with a thick layer of organic compost mixed with straw.
If you do lift them in the winter, then plant them out when the risk of frost has passed. In the south of England that wil be in the third week of May, or even the beginning of June.
If this is your first time planting out dahlias, plant them out in rich soil, in a sunny spot. Plant them so the tops are just below the surface of the soil. And plant them the right way up, which you can tell from the remnants of the previous year’s growth. Water them well and feed them regularly. The bigger the flower and the taller the plant, the more water it needs. But don’t water until the flowers are out and the plant demands water to feed its flowers and leaves.
Singles and Doubles
Singles and doubles are more tolerant of drought, and of shade. And to get more flowers during the season, deadhead dahlias repeatedly by cutting back a stem to a few centimetres above the point at which the stalk of the old head branches from the main plant.
To encourage wildlife, choose singles and doubles. Insects like open dahlias where they can see the eye and come in to feed. Compound dahlias have a less obvious landing spots, so while they are more showy, they are less attractive to insects.
My Main Concern Is To Encourage Wildlife
Now that I know something about dahlias, and given that I want to encourage wildlife more than I want a showy flower, that guides me in my choice. Frankly, if it was a choice between a lovely looking flower and wildlife, then wildlife would win every time.
Luckily, I don’t have to think about that because I prefer singles and doubles ‘in situ’ in the garden. Of course, for photographing a flower, then something more ‘present’ is a plus, but for the garden itself I am more than happy with a simpler flower.
I Bought Some Dahlia Tubers
So no surprise, I bought singles. I bought ‘Bishop Of Oxford’, which is described as a single with stunning orange flowers with a dark centre to the flowers and dark foliage. They make good pot plants as well as looking stunning in the border. Loved by bees and butterflies. height 60-70cm.
I also bought ‘Bishop Of Dover’, which is described as a lovely free flowering dahlia with white single flowers with a flush of pink, that make a stunning contrast to the dark foliage. Like with all the bishops they are much loved by butterflies and bees. Introduced in 2005 by Van Der Linden, so a relatively new one to this group, ht 60-90 cm
So the tubers will go in a south-facing border. And mentally I can look forward to photographing them for a greeting card if things go well.