Knotweeds are a large family of plants with very different members. Among them there are climbing plants as well as perennials and creeping ground covers. What they all have in common, however, is that they are all considered to be very fast-growing and difficult to keep under control. Their growth also includes their reproduction, because all types of knotweed are very easy to reproduce via seeds, offshoots or cuttings or even by division.
How do I propagate knotweed cuttings?
To propagate knotweed cuttings, cut off 10-15 cm long, herbaceous shoots in early summer. Dip the cut site in rooting powder and place it in a potting soil and sand mixture. After about 3-4 weeks you can plant the rooted cutting.
Which species of knotweed are suitable for propagation?
Many knotweeds form so-called root offshoots, i.e. individual shoots that grow directly from the rhizomes. These shoots can be dug up or separated from the mother plant and cultivated separately as an independent plant. Such propagation is preferred by Japanese knotweed, also known as giant knotweed, which can form offshoots from even the smallest root components. Other knotweeds - such as the climbing knotweed - also develop root-forming offshoots on above-ground shoots. The ground-covering carpet or piebald knotweed, on the other hand, can be easily divided.
Cut and plant offshoots
The propagation of creeping knotweed and piebald knotweed is best achieved using cuttings that are cut as herbaceous as possible in early summer. Alternatively, it is also possible to use woody cuttings cut in winter. However, since experience shows that the success rate is significantly lower, propagation from cuttings in summer should be preferred.
Propagate knotweed via cuttings
How to propagate creeping knotweed:
- Cut shoots about 10 to 15 centimeters long.
- These should not be woody yet.
- Use a clean and sharp knife.
- The cutting surface should be as slanted as possible to facilitate water absorption.
- Dip the cut site in rooting powder (€33.00 on Amazon).
- Mix two thirds of potting soil and one third of sand.
- Put the cuttings in there about a centimeter deep.
- Put a perforated plastic bag over the pot.
- Place the pot in a sunny location.
- But not in direct sun.
- Keep the substrate moist.
- Ventilate several times a day to prevent mold formation.
After about three to four weeks, you can plant the now sufficiently rooted cutting directly to its destination.
Tip
If the weather is favorable, you can take the cuttings outdoors. Either you cut cuttings and stick them directly into the soil or you propagate the knotweed - a tried and tested method, especially for creeping knotweed - using planters.
