Lilac (Syringa) is a plant with strong runners that - depending on the species and variety - multiplies uncontrollably very quickly and displaces other garden plants. For this reason, the ornamental shrub is also classified as a neophyte and should always be provided with a root barrier.
How do you use a root barrier for lilacs?
In order to prevent the uncontrolled spread of lilacs, it is recommended to use a root barrier made of high-quality, frost-, UV- and root-resistant material. The root barrier should be buried at least 60 cm deep and 1-1.5 m around the main trunk.
What is a root barrier?
A root barrier does exactly what it says: It locks the roots within a boundary and thus ensures that they cannot spread underground. They are made of durable and very stable high-density plastics, such as hard polyethylene (HDPE) or polypropylene (PP). The material is usually sold in roll form, so you can cut it to the required length yourself.
What you should pay attention to when buying a root barrier
Many gardeners try to stop their lilacs from spreading using roofing felt or pond liner. However, both materials are not suitable for this purpose as the lilac roots can easily penetrate them. Instead, even if it is more expensive, you should purchase a high-quality root barrier (€13.00 on Amazon) from a gardening store. In order for it to be effective as desired, it should have the following properties:
- root-resistant material: material of high density and strength so that the shoots cannot penetrate the barrier
- UV-resistant material: UV light weakens the strength of plastics, so that they are no longer effective after a few years. So make sure you use a UV-resistant material.
- frost-resistant material: Frost can also make plastic brittle and brittle over time. Therefore, buy a root barrier made of frost-resistant material.
- pollutant-free material: Also make sure that the root barrier does not contain plasticizers or other harmful chemicals, as this could damage the lilac.
How to install a root barrier
After you have obtained the desired root barrier, you can proceed to insert it. Of course, the principle works easiest if you bury it when you plant the young plant. But subsequent insertion is also possible. And this is how it works:
- Choose a suitable location for your lilac.
- Think about how much space you want to give the shrub.
- Keep in mind that this needs a certain amount of room to grow.
- So you should leave at least one to one and a half meters free around the main trunk.
- Dig an appropriately sized hole.
- Place the root barrier there in a ring - at least 60 centimeters deep.
- Plant the lilac in the middle.
Tip
Lilac runners should be dug up, otherwise they will sprout again from their sleeping eyes.
