Invasive plant rivals kudzu in Raleigh: What is it?

This invasive plant grows profusely in the culvert between the CSX railyard and Mulberry Street at the northern end of Blount Street in Raleigh. This plant is competing with kudzu for dominance of that no-man’s land – the area is impenetrable in the summer. It has a five-lobed leaf and small flower/seed clusters at the end of the stems. The stems, like those of kudzu, reach into the curbside grass that the city tries to maintain. I believe, if left untended, in a few years this plant and kudzu will cover the four new houses abutting the tracks.

Knowles Parker

Raleigh

Thanks for the detailed photo. I saw the lobed leaves you mentioned, as well as small, loose clusters that look like miniature, open, immature pine cones and even prickly stems – all of which led me to one plant, Japanese hops (Humulus japonicus). While this annual vine has been more of a problem up north, whether you want to blame global warming, deforestation, El Niño, Lady Gaga or the McRib sandwich, the fact is, this invasive plant – introduced from Japan in the 1800s for medicinal and ornamental purposes – has found its way into the Southeast.

Japanese hops will easily stretch to more than 30 feet during a single growing season, meaning it has the botanical brawn to duke it out with the kudzu in that culvert. But before any wannabe beer makers consider harvesting those free-range hops, cool your jets. The yields from this unwanted vine-gone-wild are minuscule, bordering on unusable for brewing.

Princess tree

What can you tell me about the princess tree? There is a 6-foot-plus specimen in my yard. Wake County Extension identified it for me. I will soon cut it down and use procedures to kill it. My gardener says this is the first time she has seen this tree, and two of her other customers have one this year, also.

Carolyn Lackey

Raleigh

The princess tree (Paulownia tomentosa) – also called the empress tree – was imported into this country in the 1830s from the Far East, but it soon escaped into the wild and is now considered an invasive plant because it has become quite a wandering bully in the backwoods.

You are actually getting off easy with your 6-footer – this green beast can quickly stretch to more than 50 feet tall, making sawing such a burly specimen down less a chore and more of an adventure. If you were instructed to cut it down to the ground and then immediately treat the stump with a herbicide containing a strong dose of glyphosate, that’s a good way to make it go away for good. The key to keeping more princess trees from popping up is to, as Barney Fife would say, “nip it in the bud,” before its seed capsules dry and are ready to spread sprouts everywhere.

Bunnies munch liriope

I’ve planted a liriope border around my trees and in front of shrubs, and no sooner do I have the plants in the ground than the alarm is sounded in the rabbit community that the buffet is open! I come out the next morning to see all my hard work chewed down to the ground. What puzzles me most is that my neighbor 10 feet away has liriope borders around every plant in her yard and they remain untouched! What gives? Any solution you have will be most appreciated! I’ve tried mothballs, cayenne pepper and garlic to no avail.

Jean Baxter

Cary

Rabbits tend to prefer young liriope plants, so if your neighbor has established stands and you don’t, that might be why they like grazing in your yard. Or if your neighbor has a cat or dog, and you don’t, and Tabby or Fido are allowed to do their necessary business outside on their property, this could also be the reason they frequent your landscape. The smell of predators – even domesticated ones – can really spook bunnies.

I noticed you have used cayenne pepper, but how about finely ground black pepper? You might have some success with it because Bugs just hates snorting in a snoot full of this sneeze powder. To keep it effective, the pepper must be reapplied after any rains.

In addition, I have used a deer repellent from a Chapel Hill company called I Must Garden and have found it to be fairly good at keeping Bambi at bay, but they also have a rabbit repellent. While I have not totally tested it – no rabbit problem at Casa Jackson – if it is close to being the deterrent that their deer-be-gone is, it is worth a try. Let your fingers do the walking and call local garden centers for it, or order it online at imustgarden.com.

L.A. Jackson is the former editor of Carolina Gardener Magazine. Send your questions, including the city where you garden, to: askthegardener@newsobserver.com.

This story was originally published October 16, 2014 at 6:06 PM with the headline "Invasive plant rivals kudzu in Raleigh: What is it?."