In our last edition of Garden Gossip, we laid the groundwork for growing Dahlias. In that column we got as far as getting your seeds and/or tubers off to an early start in the spring. Today we can pick things up by moving those pre-started plants out into the garden.
Dahlias can survive and grow under some fairly adverse conditions but if you’d like them to achieve their full potential, just a little care will go a long way. Dahlias love rich, moist but well drained soil. Very heavy soils should be amended with something like compost or peat moss to loosen them up a little. Keeping the soil loose enough to ensure good drainage is essential as wet Dahlia tubers tend to be very prone to rotting. When you plant your Dahlias in the ground, be sure to add a handful of bonemeal to the planting hole. Beyond this, don’t provide any food for the first few weeks after planting. Soil conditions should also be kept slightly on the acidic side.
For optimum bloom output, Dahlias need plenty of sun. A minimum of six hours a day is a starting point and morning sun is their favourite. A little protection from the ultra hot late afternoon sun is often appreciated by Dahlias as is protection from the wind. Dahlia flowers are frequently quite large while their stems can be fairly fragile. Couple this with the tall growth habit that so many Dahlias exhibit and you will see that even a little wind can wreak havoc on your Dahlia patch. Since Dahlias are spectacular accent plants that often find themselves in odd locations (such as the centre of a vegetable patch) sturdy stakes can be used to give them the needed extra support.
Once your Dahlias are planted, be sure to water them in deeply and then water very deeply once or twice a week, depending on weather conditions. One note here, this only applies if you are putting in plants. If you are simply planting tubers in the ground, do not water until you see some green growth or you may just cause your tubers to rot. It is also recommended to not mulch Dahlias for the same reason. As your Dahlias begin to grow you can feed them weekly but be sure to go lightly on the nitrogen or you will have a huge leafy plant with poor flowers and weak, rot-prone tubers. If you are planting the smaller bedding-style Dahlias, pinch out the growing tips after they have three or four sets of leaves. This will cause your Dahlia to become bushy and produce a far heavier blossom load. If you’ve chosen to plant the larger showy Dahlias, simply stick with the already mentioned stakes but be sure to clean off old blossoms as they occur in order to keep your plants producing new flowers. If you would like to try saving your own Dahlia seed, leave some late summer blossoms to mature and then you can experiment a little.
If you have the space where you can store the tubers over winter at temperatures of about four degrees Celsius to eight degrees Celsius, it is well worth digging your valuable tubers in the fall so that you don’t have to buy expensive new plants each spring. Wait until the first frost has blackened the Dahlia foliage. Carefully dig out the clumps of tubers and gently brush off all the dirt. Remove ant damaged and rotten tubers then hang the clumps in a cool, dry, dark place to cure. Once cured, cut the stems back to five or six centimeters and store in dry packing material such as vermiculite or peat moss and then place in your cold storage. Check your tubers periodically over the winter and remove any that seem to be spoiling. Occasionally aphid infestations can appear on overwintered Dahlia tubers. Once spring rolls around, get out your tubers and start the whole process over again.
Did you know…Dahlias were first grown in South America as a food crop. I’ve heard it said that they taste like celery, water chestnuts, carrots, Jerusalem artichokes and even potatoes. Personally, I’ve found that they taste more like turpentine. I guess taste is clearly an individual thing.
Dahlia flowers come in an incredible array of colours and forms. Over the years, many of these have come to be associated with very specific sentiments. In bouquets, Dahlias have always indicated class and elegance. Love and marriage are frequent themes celebrated by modern florists using Dahlias.
Dahlias are the official flowers of Mexico, and of San Fransisco.
The Aztec king, Montezuma, was a great fan of Dahlias and had them in his personal garden. Dahlia motifs also decorated the war helmets of Aztec soldiers and the petals of Dahlia flowers were included in the human sacrifices of the day.
And on that note, it would seem that Dahlias deserve a place in every collector’s garden!
