The bulbs of dahlias are often referred to as dahlia bulbs. Factually speaking, this is not entirely true. The storage organs of the georgine, as the dahlia is also called, are thickened roots, which in technical jargon are called tubers.
What are the special features of dahlia bulbs?
Dahlia bulbs are actually bulbs that consist of thickened roots and do not have layers like bulbs. Dahlia tubers can be divided and propagated, are late bloomers, require initial fertilization and should overwinter indoors after the first frost.
The difference between tubers and onions
Unlike onions, tubers do not consist of several layers. Dahlia shoots grow from the neck of the root tuber in different places, while onions have only one shoot in the middle.
Dahlia tubers form many new small root thickenings, i.e. tubers, over the course of the summer.
Dahlia tubers can be divided
You cannot divide an onion plant. It propagates through seeds or, above all, through small daughter bulbs that grow next to the mother plant. In contrast to the tubers, there are no visible vegetation points on the bulbs.
Dahlias can be propagated by simply cutting through the tuber. As long as at least one eye remains on the section, a new plant will grow from it. The vegetation points can be clearly seen on the tubers.
Dahlias are late bloomers
Most bulbous plants bloom early in the year. This is the case, for example, with tulips or daffodils, but also with gladioli.
Bullen plants like the georgines start to bloom later. The flowering period can be brought forward by growing indoors.
Dahlias need initial fertilization
Onion plants reproduce even when the soil is not very nutritious. The formation of new bulbs cannot be stimulated by adding fertilizer. Onion plants are therefore only fertilized later.
You can promote the development of dahlia tubers if you place the georgines in nutritious, fertilized soil as soon as you plant them.
Overwintering dahlia bulbs
Dahlias, unlike bulbous plants, are generally not hardy. After the first frost, you should dig up the tubers and overwinter them indoors. There are several ways to do this:
- Basement
- Winter Garden
- Pot
- Outside
It's best to overwinter the tubers in a dry place at a maximum of ten degrees.
Tips & Tricks
Voles really love dahlia bulbs or rather tubers. If you have a lot of these pests in your garden, it is better to plant the dahlias in a wire mesh (€9.00 on Amazon). However, this has to be quite large, as the tubers increase in size significantly in summer.
