What are the green clumps in a bare Hot Springs tree this time of year?
Those round green clumps are mistletoe, an evergreen parasite that lives on the limbs of hardwoods all year and only shows once the leaves are gone. The US Forest Service’s leaflet on mistletoes of hardwoods says the same thing from the other side: infection in a deciduous tree is easiest to spot in winter. Getting it out falls under tree trimming in Hot Springs, worked by a climber from inside the crown.
The kind that grows here is the eastern mistletoe, Phoradendron serotinum, and the Forest Service maps its range west through Arkansas. A clump is a tangle of short, forked green stems with thick leaves, sometimes the size of a basketball, sometimes a fist. Look closely at where it meets the branch and there is often a slight swelling in the wood. On older infections that swelling can split open and show soft, decayed wood underneath.
On the streets that climb off Park Avenue and Whittington, and in the Quapaw-Prospect blocks where the porches look straight up into old crowns, November is when people notice.
Which yard trees around Hot Springs carry mistletoe?
Hardwoods, and some far more than others. The University of Arkansas Cooperative Extension Service says mistletoe will take hold on many deciduous trees but is most common on elms, and that oaks, especially the upland species, are seldom hit. The Forest Service counts more than 100 species of hardwood, across about 50 genera, that the eastern mistletoe can live on.
That runs against the common name, “oak mistletoe.” The big shade trees over the old bungalows here are mostly white oak and post oak, and a clump in one of those is possible but less likely than the name suggests.
The other pattern is size and exposure. The Forest Service notes that young and small trees are seldom infected, and that the first infections usually turn up on large or old trees growing in the open. On a Hot Springs lot that is the one tree that stands clear of the others, usually the biggest, often the one over the house.
Is mistletoe hurting the tree, or just living on it?
Both, in proportion to how much of it there is. The extension service puts a light infection closer to athlete’s foot than to cancer, and only in extreme cases a killer. The Forest Service says hardwood mistletoe usually does little damage where water is not short, but a heavily infected tree weakens and slows, and in a drought it loses the branch ends beyond the clumps.
The reason is what the mistletoe takes. It makes most of its own sugar with its green leaves, but its water and minerals come out of the limb, through a root-like system that grows into the wood and taps the tree’s water-carrying tissue. One clump on a vigorous tree barely registers. A dozen on an old tree keep drawing through a dry August, when the tree has the least water to spare.
It spreads by birds. They eat the sticky berries and pass the seeds onto branches, in the same tree or the next one over, and the Forest Service notes birds keep coming back to a tree that already has berries in it, which is how one clump turns into a crown full.
There is a structural cost too. The swellings where clumps attach are openings for decay fungi, and the Forest Service warns that limbs with large or numerous infections can break under the weight of the mistletoe itself, especially in a wind.
Why is the clump back a year after it was pulled down?
The clump is only the shoot. The part that stays alive is the root-like system inside the limb, and the Forest Service says plainly that destroying the shoots does not kill the mistletoe. New shoots grow from what is left in the branch, and the infection lasts until that branch dies or is cut off the tree.
So the clump that came down with a pole from the top of a ladder last winter is back, often in the same spot. The pole and the ladder add their own damage, tearing bark around the attachment and leaving the clump broken off ragged.
Stripping the shoots still does some good. The Forest Service says it reduces the water drain on the tree, and on a big limb that cannot come off it is the practical option, repeated every few years. Wrapping the spot in black plastic after stripping it has been tried, and by the Forest Service’s account it has not worked in most cases.
How far back does a limb with mistletoe have to be cut?
Past the infection and into clean wood. The Forest Service’s guidance is to prune at least six inches below the point where the mistletoe attaches, and in practice the cut carries on back to the nearest branch collar or side limb, so the cut can close. That works when the clumps sit out on the limbs, not on the trunk.
On a big hardwood over a bungalow off Whittington, that means a climber on a rope working out along each infected limb and lowering the pieces past the gutters, not dropping them onto the porch roof. The limbs come off whole, mistletoe and all, and they leave with the brush. The Forest Service notes mistletoe on a cut branch cannot start a new infection, so nothing needs bagging or burning.
When a clump sits on the trunk or on one of the main scaffold limbs, pruning stops being the answer. Taking that limb off to get the mistletoe would do the tree more harm than the mistletoe does, a point the Forest Service makes directly. That tree gets lived with: the small infected limbs come off, the clumps on the big wood are stripped, and the tree is looked over again every three to five years, the interval the Forest Service recommends, since new clumps can surface that were too small to see the first time. Cutting the whole crown back to stubs to be rid of it is topping, and tree pruning done properly never goes there.
On most lots the mistletoe cuts ride along with the rest of the winter’s trimming, and what trimming a mature tree runs in Garland County is $300 to $850.
If you have heard about a spray for mistletoe, the Garland County office of the University of Arkansas Cooperative Extension Service in Hot Springs is where current guidance on that comes from.
How much mistletoe means the whole tree comes down?
When the mistletoe is in the trunk and the main limbs as well as the outer branches, there is no longer anything to prune it out of. The Forest Service says a tree with many infections through the crown, or on its main stems, may have to come out. On a tree that stands over the roof, dead wood beyond the clumps usually settles it.
Winter is the easiest time to read it. With the leaves down, look at how much of the crown is clump. A bare tree that shows more green mistletoe than open branch structure is carrying an infection that pruning cannot catch up with. Then look past the clumps toward the branch tips. Bare gray ends that never leafed out last spring are the dieback the Forest Service ties to mistletoe in dry years. Swellings on the trunk with the bark split open add decay to the list.
None of that alone makes a removal. A tree off by itself at the back of a lot can carry a heavy infection for years with no one at risk under it. The same crown hanging over a bedroom, a carport or the drive to a lake house on the Lakeside slopes is a different judgment, since the limbs that break first are the ones weakened by what is growing on them.
When the walk lands there, tree removal in Hot Springs takes it down in rigged pieces, and the tree that replaces it is a chance to plant something the mistletoe here seldom troubles. The county extension office can suggest which species suit the yard.