English Ivy has become quite the infestation that is now threatening our tree covered community. Each year the Narberth Shade Tree Commission works with volunteers to invest in the future tree canopy, but in parallel to this project we risk losing old growth trees. New trees require a decade to mature, but only a few minutes of yearly maintenance can protect our existing mature trees. This became quite apparent after completing the Winter 2023 Narberth area tree survey. Below, we break this threat down further...
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A mature tree is considered to be at least 10 years old, but most live many decades and some species a couple hundred years. Some of our Narberth side walk trees are over 100 years old.
Mature english ivy (hedera helix) grows 9 feet per year and thus will easily reach the canopy of a fully mature tree in less than 10 years and seriously impact health in less time. Don't believe us? Here is an example of a tree being climbed by ivy over only 3.5 years of time.
Ways that ivy harms a tree:
- vine root system steals water and nutrients from the soil before the tree can access it
- vines expand across the canopy blocking sunlight from the tree's leaves, starving it
- thick coverage holds plant debris and fungal spores compromising tree health and can attract rodents and pests (also holding moisture which attracts mosquitos)
- ivy is a sunlight oriented plant that will expand at the top creating a top heavy load on top of the tree that dramatically increases vulnerability to splitting or falling during a storm
For example, sycamore trees (with a potential lifespan of 200) are common in Narberth and this invasive pest can start to threaten their health in less than 10 years. Faster growing maples are weaker and will succumb to the added weight and sunlight starvation even faster. A smaller tree like a dogwood or ornamental japanese maple has an even shorter attack survival window.
Reasons to not allow ivy to climb in your yard:
- Physical (from a downed tree)
- Utility disruption - could cause your street to lose power or other utility services
- Property damage - can include a home, shed, fence, or car (yours or those around you)
- Landscape damage - years of growth and maintenance to maturity could be reset in an instant
- Financial
- Cost of damage - none of the above items are quick or cheap to recover from
- Property value - established maintained plantings increase the resale value of your property between 7-15%
- Legal concern
- When damage is not limited to just your assets
- Invasive plants can spread when not maintained. Township, county, and state ordinances have been passed to govern this:
- Ivy is one of the plants listed on the PA DCNR site (other plants on the PA agriculture site)
- Lower Merion Ordinance #4161 includes English Ivy: "It is hereby declared to be unlawful for any landowner or occupant to propagate, allow to grow, or maintain on land within the Township"
- Environmental
- Trees are carbon stores and air purifiers that are slow to grow/replace
- Tree canopies provide a shelter from summer heat by six or more degrees
- They are a habitat the support our local biodiversity
Ivy Warrior Mission: remediate any climbing vine threatening a community tree
Ivy defense can be handled in waves, the first being the most urgent:
- Basic - remove climbing on trees and other vegetation by cutting a "one inch moat ring" around the base of the tree on the trunk just above ground level... educate property owner on how to maintain yearly
- Protected - completely remove all ivy at the base of the tree if possible, or cut and remove ground cover ivy back 1 foot around the root flare of the tree... educate property owner on how to maintain yearly
- Removed - remove ivy altogether from the property area
- Insured - remediate area with native plantings to create an environment where ivy won't thrive again
