Mistletoe in Cedar Elms and Hackberries
Mistletoe is a parasitic plant that roots into a tree's branches and draws water and nutrients from them. In Central Texas it's most common in cedar elms and hackberries, and the way to control it is to prune out the infested branches, ideally in winter when you can see every clump.
How It Gets There
Birds eat the white mistletoe berries. The seeds inside are sticky and get wiped or dropped onto branches, where they germinate and push a root-like structure through the bark into the wood. From there the mistletoe taps the branch's water supply. It does make some of its own food from sunlight, which is why it stays green, but it depends on the tree for water and minerals.
Because birds spread it, mistletoe clusters. One heavily infested tree tends to seed the trees around it, and hackberries along a fence line, where birds perch all day, can be loaded.
Why Cedar Elm and Hackberry
Mistletoe can grow on many trees, but in this part of Texas it strongly favors cedar elm and hackberry, with bois d'arc another common host. Live oaks are rarely bothered by it. If you see green clumps in a live oak, look again; it's more likely ball moss.
Mistletoe or Ball Moss?
| Compare | Mistletoe | Ball moss |
|---|---|---|
| Color | Green, leafy | Gray, wiry tufts |
| Berries | Small white berries in winter | None |
| Usual trees | Cedar elm, hackberry, bois d'arc | Live oak and other oaks, especially shaded inner branches |
| Takes from the tree | Yes, water and minerals | No; it gets moisture from the air |
| What to do | Prune out infested limbs | Usually just thin the canopy for more light |
What Mistletoe Does to a Tree
A few clumps won't kill a healthy tree. Mistletoe works slowly. Over years, a heavy load:
- Weakens the branches it's rooted in, which often die back beyond the clump
- Shades out the tree's own leaves
- Adds water demand during drought, which is the real danger in Texas summers
- Leaves the tree less able to handle heat, drought, cold and pests
Trees that are already stressed, like cedar elms left standing on a lot after construction, decline faster with heavy mistletoe.
How to Prune It Out
Pulling or snapping off the green part doesn't work for long. The root-like part stays in the branch and regrows. The effective approach:
- Do it in winter. Once cedar elms and hackberries drop their leaves, the evergreen clumps stand out clearly.
- Cut the branch, not just the clump. Remove the infested branch back to a healthy side branch or the trunk, at least a foot below the visible clump if possible. That gets the parts embedded in the wood.
- Keep it reasonable. Don't take out so much at once that the tree is stripped. On a heavily infested tree, spread the work over two or three winters.
- Get young clumps early. Small new clumps on small twigs are easy to remove. Waiting lets them spread and grow into major limbs.
- Follow up. New clumps show up every year if neighboring trees still carry mistletoe.
There's no spray that selectively kills mistletoe without harming the branches around it, so pruning remains the practical tool.
When It's Too Far Gone
If mistletoe has grown into the main trunk or the largest limbs, removing it would mean cutting off most of the tree. At that point the honest choices are to live with it or remove the tree, particularly if it's a hackberry, which is often the case. A cedar elm worth keeping might get partial cleanup and better watering. A hackberry crowded with mistletoe and leaning over the garage is usually a removal. Is a hackberry worth keeping?
Can You Stop It Coming Back?
Not completely, as long as birds keep visiting trees nearby that carry mistletoe. A few habits keep it manageable:
- Check cedar elms and hackberries every winter and remove new clumps while they're small.
- Talk with neighbors. One heavily infested tree next door will keep reseeding yours, and some streets coordinate winter pruning.
- Keep trees healthy with deep watering during drought. Strong trees hold up to a light mistletoe load much better than stressed ones.
Getting It Done
Pruning mistletoe high in a tree means climbing or a lift, and cuts should be made properly at branch unions. A crew can remove infested limbs during winter tree trimming, or take down trees that are past saving. For do-it-yourself pruning on small trees, the local Texas A&M AgriLife Extension office has guidance.