Dahlias eye catching and vibrant
AS summer turns to autumn there is no other plant that can beat Dahlias at providing the most eye catching, vibrant and vivid colours in the garden. In fact Dahlias are pretty hard to beat in that regard even when compared to spring and summer flowering plants. Such is their variety in bloom that they can be all things to all people. But equally such is their variety that few people love them all.
For me at their best they are style and elegance personified and at their worst they are brash and gaudy. You can make up your own mind on which Dahlias you do and don’t like but one thing is for sure none of these spectacular autumn flowering plants are shrinking violets.
Native to Mexico, Dahlias were discovered growing in the gardens of the Aztecs as far back as the 1500’s where they were used for both culinary and medicinal purposes. It wasn’t until much later in the 1800’s when two species were crossed to form a hybrid that we got something like the Dahlias we know today. There are now 50,000 named varieties, books dedicated solely to them and societies affiliated to them.
Dahlias grow from root tubers which are thickened energy storing roots that grow underground. Sweet potatoes are also root tubers while our beloved potato is a stem tuber. Basically one is a modified root the other a modified stem in botanical terms. Both store energy for the plant to produce new growth in the following year. Dahlias can also be grown from seed and from root cuttings
To enter into the murky world of Dahlia flower classification here would be a time comsuming mistake that could lead me into a matrix on the internet from which I may never emerge. To say that there are 14 generally excepted flowering groups before sub classifications that also have sub classifications is enough.
To enjoy and to get the very best out of your Dahlias plant tubers in a full sun position in good well drained soil with added manure / compost and a hand full of general fertiliser. The dry tubers will be grouped together and attached to a cut back stub of last years stem, this should be planted just below the soil level. Dig a hole approximately 30 centimetres square to accommodate the tuber incorporating the manure/compost and fertiliser. It is generally advised that this planting is done once the threat of frost is over. You can start off your tubers in large pots in a sheltered spot or greenhouse and transplant them out later if you’d rather. This method will give you earlier flowering plants.
Bedding Dahlias, first year plants without tubers, are also available as seedling plants around the end of May and require the same conditions as your tubers. If you are growing a few varieties of Dahlia it may be fun to save some seed for sowing next spring and see what emerges. Because the Dahlia has likely been cross polinated with another different Dahlia it won’t come true to the parent plant but could be a new form equally wonderful instead. A tuber lifted is a vegetatively propagated plant so will remain true to the parent plant.
Tall growing Dahlias require staking, it is essental. Failure to provide adequate support and your Dahlia will flatten in the first heavy rain or wind. You can do this with four heavy bamboo canes banged into the soil and create a wire supporting cage around the plant from these.
Lifting Dahlias in the winter has always been advised but of late I have heard of more and more gardeners, including myself, leaving their Dahlias in the soil year after year. Personally I have had no problems and am prepared to take the chance of losing them over a few years, albeit with the precaution of providing a compost mulch over them to help them out. I tend to lift every three year anyway to divide and replant.
Slugs and earwigs can be a problem with Dahlias so be prepared. Dead heading is advisable to encourage new blooms to be produced and Dahlias make great cut flowers. As plants go there is little better value to be had than with a Dahlia, cheap to buy and with a flowering capacity of July until even as late as November.