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Monday, September 12, 2016

Privet and Ligustrum: plants to NEVER plant


 

 Privet invades a landscape quickly, growing into thickets that crowd out native plants and change the very ecology of an area. Even if the shrub can be removed effectively, it’s tough for a landscape to return to its previous condition.

Actually, privet and ligustrum are two names for the very same plant. First introduced into the U.S. in 1852, Chinese Privet (Ligustrum sinense) escaped cultivation by the 1930s and spread across the Southeast.  “Chinese privet is the primary cause of the decline in diversity of native herbaceous plants and tree seedlings in the areas it infests.” said research entomologist Jim Hanula.

Results from a five-year study published by U.S. Forest Service researchers showed that not only can a thorough removal of privet last at least five years without a follow-up, but also that native plant and animal communities steadily return to areas cleared of the invasive shrub. Hanula and Horn began investigating how privet removal affected the recovery of plant and animal communities by comparing the treated plots to reference areas that had never been invaded by privet and control plots that were invaded and not treated. The results were dramatic,” said Horn. “The hardwood forests we’re working on are some of the most beautiful places in the South when they’re not choked with privet. We saw the return of native plant species in all of the treated plots.”

Results from their studies on pollinators were even more dramatic. “After only two years, there were four to five times more bee species in privet-free areas, 40 or 50 compared to the 10 on control plots infested with privet,” said Hanula. “We caught three times as many butterfly species on the mulched plots and nearly seven times as many individuals.”  “Overall, these results are encouraging, since we expected to have to re-treat the privet more frequently to preserve the integrity of the removal plots,” said Horn. “These results show that control following one removal event lasts at least five years.”

Ligustrums are notorious water guzzlers, pilfering water from more desirable plants. Around homes, fall is a great time to pull them out of the ground (they’re extremely shallow-rooted). Large plants can simply be cut at the base with pruning shears. Then, plant a few native plants, or let the natives re-fill naturally.

 

Owen Yost, in addition to blogging, is a Landscape Architect emeritus from here, whos worked in north Texas for over 30 years.  He is a member of the American Society of Landscape Architects (ASLA), International Society of Landscape Architects, the National BirdFeeding Society, National Wildlife Federation and the Audubon Society. He was honored with a Lifetime Achievement award by the Native Plant Society of Texas. His design office is at northwestern68@yahoo.com

 


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