Tree Care: What Causes Brown Leaves on Trees?

And Other Issues Affecting Our "Gentle Giants"

Close-Up Of Dry Leaf On Tree Trunk
Damjan Prskalo/EyeEm/Getty Images

Tree care is a critical investment for the future of your landscape. So while brown leaves, dead limbs, and the like don't always mean you have a dying tree, it's important to take notice of such troubling signs and learn their causes. The following are some of the dividends you'll earn on your investment in caring for your yard's gentle giants, assuming you handle it correctly:

  • Increasing property values
  • Beautifying your surroundings
  • Purifying your air
  • Saving energy by providing cooling shade from summer's heat and protection from winter's wind

I receive many questions about tree care from readers, a sampling of which I've provided below.

Why Are the Leaves on My Japanese Maples Turning Brown?
There's a reason that Japanese maple trees are among the most popular specimens in the landscape. Their leaves look wonderful throughout the growing season, not just in autumn. For fall foliage colors, they offer gold as well as red. So-called "dissected" types exhibit interesting leaf shapes, to boot. But with Japanese maples, it is not uncommon to see the leaves turning brown in summer. Click the tree care link above to learn why this problem occurs.

Why Do I Have Brown Leaves on My Magnolia Trees?
Unlike Japanese maples, magnolia trees have something besides foliage to brag about. Magnolia trees are one of the most popular specimens in the spring landscape, due to their beautiful blossoms.

But the appearance of brown leaves out of season is a troubling sight on any specimen. Consult the FAQ linked to above to learn why context is everything when it comes to asking why your magnolia trees have brown leaves.

My Magnolia Trees Have Not Only Brown Leaves But Dead Branches. How Much Should I Prune?


If brown leaves scare homeowners, then dead branches should send them into shock! But wait; all is not lost, necessarily. When you detect dead branches, the tree care task awaiting you involves both action and scrutiny. Above all, remain calm, and consult the FAQ linked to above.

My Young Bradford Pear Tree Now Has Brown Leaves That Are Wilted. What's Up?
Bradford pear trees flower profusely in spring and afford excellent autumn color. But the experts warn that it's a mistake to plant Bradford pear trees, and rightly so: their limbs break too easily in stormy weather. I've seen the limbs of too many Bradford pear trees lying on the ground after a good wind to buy one, myself. But if you've already planted a young Bradford pear tree, your hope is that, through proper tree care, you can derive as many years as possible from your specimen. Your tree care work may well begin with the challenge represented by the FAQ linked to above.

My Magnolia Trees Developed Brown Leaves. The Foliage Also Got Black Spots on It. The Leaves Fell Off. What's the problem?
Have black spots on your magnolia tree foliage? Find out what they are -- and what you can do about this problem.

The Leaves on My Bradford Pear Tree Are Turning Brown. Should I Give It More Water?


As the answer to this FAQ reveals, you can't automatically assume you need to water a tree more just because it has brown leaves when its foliage would normally be green.

The Leaves on My Emerald Cedar Tree Started Turning Brown Last Summer. What's the Problem?
This problem regards browning on a plant actually named 'Emerald Green' arborvitae, but some people use the nickname "Emerald cedar." Find out the possible reasons why this plant's foliage might turn brown in summer.

Tree Problems Caused by Insects

Insect pests can wreak havoc with trees. And what makes tree problems caused by insects especially difficult to cope with is that, sometimes, the pests we detect on a tree aren't the ones causing the problem. Below I present a sampling of Q&As dedicated to this topic:

My Red Spruce Trees Are Being Attacked by Insects (Beetles). How Do I Stop the Spread?


Speaking of deadly attacks on trees from insect pests, certain beetles can spell major problems for your specimen trees. As I explain in the FAQ linked to above, proper tree care, in this case, demands good timing and a belief that neatness counts.

Scale Insects Have Infested My Magnolia Tree. How Do I Control Magnolia Scale?
Scale insects are among the oddest looking insects you'll ever see. Click the link to this FAQ to learn how to control magnolia scale.

My Young Blue Spruce Tree Is Developing Bare Branches. Is It Dying?
Insects may be the culprits here. Consult this FAQ to find out which insects would be the "usual suspects" -- and how to control them.

What Pest Makes Those Little Holes in a Tree? Is It an Insect?
As you'll see in the answer to this tree problem question, it all depends on the nature of those "little holes." In one scenario, you don't have to worry about the culprit; in another, the culprit is an insect pest about which you very much need to worry.

How Do You Treat Ants and Sooty Mold on a Magnolia Tree?
If your tree is struggling and has insects on it, you can't just assume that those particular insects are at the root of the problem. Here's a case where insects (ants) and sooty mold are effects, rather than the cause of a problem.

Yellow Leaves on Trees - What's the Reason?

Your tree has yellow leaves. Does that yellowing signify a tree problem? Well, it depends on the circumstances. Obviously, if you grow fall foliage trees and they are displaying that color in fall, there's a good chance that the foliage is supposed to look that way. But what about other times of the year? Or what about other types of trees?

Well, it still depends on the circumstances, as you'll discover by clicking the first two links below dealing with the issue of yellow leaves on trees.

My Southern Magnolia Has Yellow Leaves. Is It Dying?
We begin with a case of yellow leaves on a southern magnolia.

Why Did the Flowers on My Bradford Pear Turn Black?
In this FAQ, the operative color is black, not yellow.

Fire blight disease is so called because it causes tree parts to turn black. Find out how to treat fire blight by reading this tree problem FAQ.

Does It Help to Fertilize an Injured Tree?
Fertilizing has its place in tree care, but does it play a role in nursing an injured tree back to health?

My Magnolia Tree is Getting Too Big and I'd Like to Make It More Compact. What Is the Best Time for Pruning Magnolia Trees?
In this FAQ, I answer the question of when to prune magnolia trees -- but with a caveat.

How Do You Care for a Potted Magnolia Tree?
It's easy enough to fulfill sunlight requirements for a potted magnolia tree, but proper watering isn't so easy to achieve.

Why Isn't My Flowering Tree Blooming?
A "flowering tree" not flowering: Is that a contradiction in terms? Well, Mother Nature apparently doesn't see it that way. Find out some of the possible reasons why a flowering tree might fail to bloom.

How Do You Straighten a Leaning Tree?
If your tree leans and you've tried -- but failed -- to straighten it out, you'll want to consult the answer to this tree problem FAQ.

Why Are My Dwarf Alberta Spruce Trees Experiencing Needle Drop?
Needle drop on evergreens can be scary, but it's not necessarily fatal. Learn what may be causing needle drop on your evergreen tree -- and what to do about it.

Can You Spread Soil Over Exposed Tree Roots and Grow Plants on Top of Them?
This isn't the best of ideas, and I explain why it's not in this FAQ, offering an alternative.

Winter Damage to Trees

In the following entry, I discuss another problem: a case of coping with the challenges posed by warm climates. In the last two FAQs, I point to examples where tree "damage" might be your first thought upon observing strange growths (bumps) on trees, but they turn out to be nothing harmful.

Do You Have Any Tips for Protecting Japanese Maple Trees From Snow and Ice Damage?
In addition to some of the more direct steps you can take to protect Japanese maple trees (and others) from winter damage, this FAQ looks at some less obvious steps that you could easily overlook.

Our Bradford Pear Lost Limbs From Snow and Ice Damage. What Should We Do?
Some tree problems are the result of poor plant selection. Bradford pear trees are notorious for losing branches due to wind, ice and snow damage.

Why Don't the Buds on My Magnolia Tree Open Up?
There are a number of possible answers to this question. I offer three potential reasons why magnolia buds fail to open in this FAQ. Two of those reasons are weather-related.

Can You Grow Dwarf Alberta Spruces in Pots in Warm Climates?
Dwarf Alberta spruces are best grown in zones 3 to 8, but this reader wishes to "break the rule" -- or try to, anyhow. I suggest a way to "cheat" that might make it possible to grow dwarf Alberta spruces in warm climates.

What Are Those Odd-Looking Growths on My Magnolia Trees?
Although our trees sometimes exhibit signs of having been damaged, some tree "damage" turns out, upon further inspection, to be a false alarm. We detect something (perhaps something we'd describe as an "odd growth") we've never noticed before, and it worries us -- until we've undergone the necessary learning process to find out what the heck it is! Such is the case in this FAQ, which you can access by clicking on the link above.

The Leaves of My River Birch Tree Have Growths on Them. What Problem Does My Tree Have?
Another case of "mysterious growths" or bumps -- but once again, nothing that indicates any serious damage.

Why Should I Be Watering Evergreen Trees in Autumn?
Hint: It's a matter of thinking ahead.

When Should I Be Watering Trees in Fall?
You know the "Why?", now learn the "When?"

When Should You Fertilize Trees?

In general, fertilize trees in spring. This will result in surprisingly vigorous new growth, including a thicker leaf canopy. The foliage will also display a richer color as the result of the application of tree fertilizers. By the way, yes, you should still apply tree fertilizers even to older specimens, even though it's natural to think that they're "big enough already." They need the nutrients to stay healthy. 

What Is the Proper Way of Pruning Trees?

There are many different kinds of pruning cuts, but the following tips will give beginners the basics of what they need to know about the proper way of pruning trees, generally.

If you must prune off a scaffold branch (see below), make sure, first of all, that the branch does not begin to fall prematurely, while still attached to the trunk. This would cause a rip at the joint where the branch meets the trunk, thus creating an open sore that invites disease. To avoid this scenario, make your cuts in the following manner to reduce pressure on this joint:

  1. At a point along the branch approximately 2-3 feet away from the trunk, begin by sawing about half way through the branch from the bottom.
  2. Now, from the top, but an inch or so further out from the branch than the first cut (more for thicker branches), saw through the rest of the branch, to remove it. You've now removed all but 2-3 feet of the branch. The remaining stub won't weigh enough to put undue pressure on the aforementioned joint.
  3. Now proceed to prune off the remaining stub, as indicated below.

With the danger of ripping thus eliminated, we can prune off the remaining 2-inch to 3-inch stub. To do so, acquaint yourself with a tree part known as a branch "collar." A branch's "collar" is the swelled base of the branch where it meets the tree trunk. Think of it as an intermediate area between the branch and the trunk.

To finish pruning off the branch, saw it off just outside the branch collar. Leaving the branch collar intact will promote healing.

If you are merely shortening a scaffold branch on a young tree, prune the branch back to a lateral bud or other branch. 

What exactly is a "scaffold branch?" A scaffold branch is one of the primary limbs radiating from the trunk of a tree. All subordinate limbs stem from the scaffold branches. By establishing what the latter will be for a particular specimen early on, you can prune accordingly and shape it so as to achieve optimal form. This is one of the most important aspects of early tree care.

What Is the Best Time to Prune Trees?

You can cut dead or diseased branches off trees (whether evergreen or deciduous) at any time of the year, as soon as you see them. But what is the best time to prune trees, with the intention of thinning out healthy branches? The job is best done, generally speaking, in late winter. For example, pruning oak trees at this time will help avoid problems with oak wilt, to which the trees are more susceptible April-June. An exception can be made for plants with a high sap flow in late winter, such as maple trees. The best time to prune such trees is late spring or early summer.

In thinning out trees, you'll be removing branches that are alive and disease-free, but ill-positioned or otherwise undesirable. For instance, you shouldn't have any two branches of your trees coming into contact with each other. Such contact invites disease and an overly thick canopy casts too much shade on the tree's lower branches.

True, in the case of flowering trees (such as weeping cherry trees), specifically, pruning off such branches in late winter may lessen the impact of the specimen's floral display for that year. But in the long run, the pruning will be beneficial.

The following links take you to answers to some specific questions about pruning trees:​
What Tips Can You Offer on Pruning Arborvitae After Snow Damage?