The Q&A Archives: out-of-control Ligularia Dentata

Question: As part of a very large (1200 perennials installed plus 3 specimen trees and several evergreen shrubs) planting bed surrounding one side of my pool, ligularia dentata was planted. Seven years later, the ligularia is overtaking the entire area, with some plants shooting up as far as 30 feet away from the others. For the past several years, I've been pulling out the plants that have appeared outside of the area they're supposed to be in, but this year, I'm losing the battle. The ligularia has overtaken several other areas, crowding out and killing off quite a few grasses and other perennials. Is there any way to control this? I would like to keep the original planting area with this plant, but little by little, I'm losing the other plants and will soon end up with 65' of nothing but ligularia. Do you have any suggestions for taming this thing?????? Thank you for any help you might offer.

Answer: I am somewhat surprised to hear that a Ligularia is being invasive. Usually it is somewhat difficult to grow it well. Here is a photo to see if this is really the plant.

I am wondering if it might be a Lysimachia (notoriously invasive) instead?

Or possibly a look-alike Petasites, also known as a terribly invasive plant especially in damp soil.

All three of the above plants thrive in moist rich soil. If you are fertilizing or watering the area you could consider stopping while you try to eradicate the problem plant. To slow the spread, first prevent the plants from setting seed. Then begin by digging them out as best you can. Lysimachia will regrow from any shred of root left in the ground. Then use an herbicide such as glyphosate, be sure to read and carefully follow the label instructions. When plants have invasive tendencies and strong root reserves, it can take several applications over a period of time to achieve full control. Since this is intermingled with other desirable plants you may find the wipe-on application method is better in terms of protecting the plants you want to keep. You should also try to mulch the area to prevent seedlings from emerging.

If the roots have worked their way throughout the area you may have to clear it and then start over once you are certain the invader is controlled. If it is this invasive I would suggest you not even try to keep a small patch of it as it will always be a problem.

Your local county extension may also have some control suggestions and may be able to help you identify it for sure as well. I'm really sorry you are having trouble.

« Click to go to the homepage

» Ask a question of your own

Q&A Library Searching Tips

  • When singular and plural spellings differ, as in peony and peonies, try both.
  • Search terms are not case sensitive.

Today's site banner is by Char and is called "'Diamond Head' Sunrise"