Dahlias are Wonderful Cut Flowers
A long time ago in a garden far, far away, my bride cut some dahlias to take to work, and set them on the sofa for a few seconds so she could collect her purse and coat. Dozens of nasty looking earwigs popped out of the flowers and invaded the sofa. It took a long time to get rid of all the earwigs, and as a result we stopped growing dahlias because we were afraid to bring the flowers into the house.
A couple of years ago it was apparent that our rose garden was failing. Too much attention required and too little given. We had seen a dahlia display garden on a wine trip to Seattle, and noted the varieties we liked best. So out went the roses and in went dahlias, planted according to the instructions that came with the tubers. Here’s what happened.
The first year we visited our new dahlia garden only about once each week, cutting flowers for indoors and deadheading to promote more bud production. A combination disease and insect control spray (often sold for roses) was applied monthly, and this prevented fungus and earwig attacks. We fed the plants only twice, in early May and again in June, using a fertilizer with a high middle number (like 5-10-5). This kept the dahlias happy all season.
The second year we limited each plant to 3 to 4 stems to avoid crowding. We still had plenty of flowers, but the blooms were larger. Then we purchased additional dahlias from a supplier that sold rooted cuttings, and these grew just as well as the tubers. Now from early summer until the first hard freeze our dahlias provide a great display visible from 100 yards away.
Lessons learned (so far): The instructions said it was okay to plant tubers 1 or 2 feet apart, but this was too close. Adjacent plants quickly started to intermingle, making pruning, deadheading, and spraying difficult. This spacing might have been okay if each plant were limited to one stem to maximize flower size. But since we allow 3 to 4 stems per plant, keeping plants 4 feet apart has made maintenance easier.
Dahlias get top heavy with flowers, causing stems to snap, especially after a rain. So the planting directions recommended putting a stake in the ground next to each tuber when planting (inserting the stake after planting risks spearing the tuber.) I drove a quarter-inch diameter steel stake a couple of feet deep, but this wasn’t strong enough to support multiple stems. A heavy duty green steel fence post worked better.
The nursery advised that we could leave tubers in the ground all winter in Zone 6. But they recommended that the planting area be covered with a tarpaulin or plastic sheeting after the first hard freeze in fall, to prevent the tubers from rotting over the winter in wet ground. This has worked well; every plant has re-sprouted the following spring.
Even though we were warned to watch out for slugs, they have not been a problem, possibly because the dahlia bed is behind a masonry wall 3 or 4 feet above the adjoining ground.
A teaspoon of white vinegar in a gallon of water keeps cut dahlias fresher longer.
Try growing dahlias in a sunny spot in your garden. For us they have been less labor intensive than traditional roses, and provide many more flowers for cutting. Several local growers offer a large selection of varieties.
Jim Janke is an Extension Master Gardener Volunteer in Haywood County. For more information call the Haywood County Extension Center at 828-456-3575. © 2013 NC State University.