Dancing into autumn with dahlias
Autumn can feel like the beginning of the end of the gardening year. But there’s still lots to enjoy in the soft autumn light that can surprise and delight us. It’s tempting to write off the season and think the season is full of boring tidying up jobs.
Top of my list of early autumn favourites to relish are the dahlias. While they started to come into bloom in August this year, they are still going strong in the gardens around here well into October. With literally hundreds of varieties, there is a variety for all. You just might not have met it yet! The flowerheads come in a range of shapes too. Catcus and pompom shapes are popular, though the single flowered ones are the best for pollinators. Getting enough nectar is important for pollinators to see through the winter - it’s the equivalent of putting on a jumper or getting out the autumn boots.
Of the single flowering dahlias, I have a special soft spot for the “bishop” series. These all have strong, purple stems, giving dramatic foliage as well as high impact flowers.
To enjoy dahlias at their best, keep deadheading regularly. To deadhead dahlias, cut off the flower and stem where the stem meets the next pair of stems with buds on. This will encourage the flower buds on the end of those stems to flourish. They are great as cut flowers, and can even be dried for winter decorations.
When do I deadhead dahlias ?
Sometimes it is hard to tell the difference between a bud which has not yet come into flower and a finished dahlia bud. Get a pot of coffee and some snips. Give each bud a gentle squidge - if it is hard and round, it’s a new bud so don’t cut it off. If the bud is a bit soft and cone shaped, it’s finished, so snip it off.
What about winter?
When the first frosts come, the stems of anything green and lush will go brown and slushy. Dahlias are one of the key indicators of when an overnight frost has happened, as the wilting happens almost instantly. Cut off the topgrowth to about 10cm above the soil to avoid rot and water going down into the plant.
The jury is out on whether to leave dahlia tubers (the knobbly potato-like bulbs) in the ground during the winter or not. Dahlias are originally from Mexico and the received wisdom for many years was that they needed to be lifted out of the ground and stored somewhere frost free before re-planting in spring.
However, did you know that in some parts of Mexico the winters can get extremely cold - much colder than in Hampshire? A couple of years ago I stopped digging mine up, and just put a pile of mulch over the tuber patch. So far, I haven’t lost a single one.
That sounds a bit risky to me!
Of course, if you know your prize dahlias will be in a soggy and frosty pocket this winter, whip them out, but gardening is all about learning through experimentation - and the faff and work of digging up lots of dahlias and finding space to store them in the cool and dark is something I am happy to give up. The real enemy is not so much the frost, but wet winters getting to the tubers under the soil and rotting them in combination with the low temperatures.
If you do take them out, wrap them up in newspaper and store somewhere dry and cool out of direct light. You effectively want them to go into suspended animation before bringing the tubers out into the light and putting them in fresh compost in the spring.
Remember, autumn is a season to be enjoyed and delighted in for it’s own right, and not just as a month to pass us by. And if we remember that October is as long as May, we might be able to rethink how we use our green spaces – for the benefit of us as well as the plants and animals we live alongside.
This Editorial Note first appeared in the Basingstoke Observer, 13th October 2022. All rights reserved.