Cedar trees should have some needles that go brown and shed, while some shouldn’t. What’s normal, and what ain’t?
Cedar trees normally undergo browning and shedding of some of their inner needles each autumn. This can occur excessively where there is poor soil drainage, winter desiccation, or after recent transplanting. The position and timing of needle drop can aid in diagnosis.
One of my favorite trees to admire is about 2 miles from my home – a particularly large and graceful deodar cedar (Cedrus deodara). Here’s a photo (it’s a few years old, judging by how old my kids look!):
I pass by this tree often. This year, I’ve noticed it’s lost more of its needles than usual and many have become brown, especially on the inner parts of the tree. This got me interested in how cedars compare with other evergreens such as pine and spruce in terms of dropping needles.
I love to research trees and have a huge library of books that I’ve used over the years to enhance my hands-on tree-care knowledge.
If you suspect you might have a problem with your cedar tree, read on and I’ll help you work it out.
The genus Cedrus is a small one – there are only four recognized species of ‘true’ cedar tree, while a whole host of other trees are commonly called cedars, but are really false or ‘faux’ cedars!
This can make it all the more confusing for tree owners to work out what the problem is with their cedar tree.
The ‘true’ cedars (Cedrus species) are:
- Cedrus atlantica (Atlas or Atlantic Cedar. Blue atlas cedar would be the best known, particularly the graceful ‘Glauca’ variety)
- Cedrus libani (Cedar of Lebanon. Mentioned numerous times in the bible as a symbol of strength, durability and beauty)
- Cedrus deodara (Deodar cedar – native to the western Himalayas)
- Cedrus brevifolia (Cyprus cedar – the least often seen and cultivated; smaller than the others)
There are many false or faux cedars! Here are several of them, all belonging to other tree families ¹:
|Western red cedar
|Eastern red cedar
However, many of the principles in this article will apply to all ‘cedar’ trees, false or otherwise.
When do cedar trees lose their needles?
Cedar trees normally hold on to their needles for up to four years before they are shed. They should only shed the older needles, which go brown before falling from the inner parts of the lower branches. Around a third of inner needles will drop in late summer and early autumn.
Abnormal cedar needle drop
So when is cedar needle shedding NOT normal? Well, those needles close to the branch tips should always stay on the tree and stay a healthy green, unless they’re right at the base and are being shaded out by higher branches.
Browning or shedding of needles at the tips is abnormal, and a sign of tree disease or stress. Likewise, if the tree’s lost more than a third of its inner needles, but the outer ones are still intact, that’s another possible sign of a stressed cedar.
As mentioned above, cedar needles tend to go brown BEFORE they fall from the tree. So if you’re seeing a lot of brown needles, it may be a matter of time before they drop off.
To give a more complete list, something’s wrong if:
- You’ve got browning/shedding at branch tips
- You’re losing well over a third of inner needles in late summer/autumn
- You’re getting needle drop in winter, spring or early summer
- The shedding’s not symmetrical – it affects one side more than the other, or just the top
- The fallen needles have spots on them, or aren’t uniformly brown
- The trunk or branches are oozing sap from sunken wounds – ‘cankers’
The last 2 of these in particular are signs of infectious disease. Read on.
Stressors that cause abnormal cedar needle drop:
Cedars are typically quite drought-resistant when they’re established, particularly the deodar cedar. Young trees however do benefit from watering once weekly during the summer months.
More the issue though is cedar’s well-known intolerance for ‘wet feet’, which flood the roots. It’s difficult to get a cedar to flourish on a waterlogged site; you can expect to see a cedar that looks sickly – it won’t grow as you expect, and will lose more needles (particularly inner needles) than the usual 30%-ish.
If you’ve recently planted, it may be easier to transplant the tree to a site that’s better drained.
In common with its dislike for overwatering, I’ve found that many cedars – particularly when planted ornamentally – are surrounded by densely compacted soil, overworked by heavy machinery. The squeezes the air from the soil, making it unavailable to the roots. When planting, make sure the soil is well-worked.
Cedars usually grow best in acidic soil (pH <7). If you’re soil’s alkaline, it may struggle to get itself established.
Again you’re more likely to see an excessive loss of inner needles in late summer and autumn.
Cedars like full sun, and even partial shade will prevent some from growing properly. A cedar in the shade will see excessive inner browning and needle loss, as those needles which get minimal sunlight will have no value (no sunlight = no photosynthesis).
If you ask me, a cedar looks better out on its own anyway, in all its glory. Not a tree to plant down the side of your property, or in a shady corner of your yard!!
This is something to consider if you’re seeing needle drop on a tree that’s been planted in the past 3 years. It might cause excess shedding from inner branches, but also some browning and shedding at the tips of branches too. It’ll be most prominent in the 6 months following transplanting from a container or another site.
Cedars can be tricky to successfully transplant at the best of times. The state of stress after transplanting is known as ‘transplant shock’. Essentially, the roots take time to adapt to their new environment, so there’s a temporary induced drought-like state where their water uptake’s diminished, and the normal fluid movement through the tree is disrupted.
Needles that have already turned brown will fall and won’t grow back. But provided your tree’s on soil that’s well-drained, you can usually nurse a cedar through transplant shock with regular watering.
A heavy root-soak once a week during warm weather and once a month during the colder months (provided the temperature’s safely above freezing), and your cedar will come around with time.
Cedar trees can struggle in urban environments where traffic or industry contributes to air pollution. The Cedar of Lebanon’s reportedly the most pollution-tolerant, but it’s still a significant cause of cedar tree stress that can cause excess browning and needle drop, particularly from the inner branches that receive less sunlight.
Cedars, in common with pine and spruce, are susceptible to ‘winter injury’, also known as winter dessication or winter burn – browning and excessive loss of needles in late winter or in spring caused by excessive moisture loss from needles during the winter, particularly at the branch tips.
Deciduous trees shed their leaves in winter so they don’t lose moisture from them. The evergreen cedars however continue to lose moisture from their leaves (needles) all winter – particularly so in heavy winds, and especially so when the ground’s frozen – so the roots can’t draw up water to replace that that evaporates from the branches.
Winter injury can often give an asymmetrical look to the browning and needle loss, such as:
- browning at the tree top, farthest to the root and exposed to wind
- browning the side most exposed to wind
- browning on a side that’s sprayed with road salt, which greatly increases the risk of winter injury.
Winter injury isn’t usually lethal to a cedar unless it’s very young – in this case, you’ll see the whole tree go brown in late winter or early spring.
It’s important to give young cedars some wind protection and to water them through the winter to prevent desiccation.
You can provide basic wind protection with burlap or plastic sheeting. Watering should be undertaken on a monthly basis, as long as the temperature’s above freezing – freezing the roots will make the problem worse.
An easy thing that’ll help is to apply a four-inch layer of organic mulch, such as bark chippings, around the base of the tree – about a 5-foot diameter ideally. The mulch will insulate the roots from temperature changes, and help water permeate to them. It’ll suppress growth of grass and weeds, which will compete with the young tree for moisture.
Just avoid piling the mulch up against the trunk – leave a slight gap to prevent trunk rot.
Here’s a helpful video from University of Connecticut Extension about correct mulch application.
Cedar tree diseases:
Cedar tree needle blight
Sirococcus needle blight is a fungal disease of cedar and hemlock trees that was initially recognized in the western United States in the 1960s, but has spread to the east coast US. It’s known to be present in Europe, including the UK and Ireland, since the mid-2010s. It’s sometimes called Sirococcus tsugae.
Similarly to other needle cast diseases, this fungal ailment causes browning and needle drop at the tips of shoots and branches, and can cause dieback of entire shoots, or even whole branches.
Suspect needle blight if:
- Branch tips are turning pinkish or brown in the summer (particularly following a wet, cool spring) before falling off
- It’s worse in the lower branches (particularly in mature trees)
- On close inspection, the discolored needles have tiny black spots on them (‘fruiting bodies’, containing fungal spores)
- You may see cankers – sunken, oozing ‘wounds’ in the bark of infected branches, or in the trunk.
Sirococcus will usually not kill cedars (unless they’re young) but can significantly weaken them and make them look sick and unappealing.
However, like most fungal tree diseases, it’s highly unlikely you’ll ever cure your tree. Instead, the aim of management is control – through cultural practices:
- prune off any diseased-looking parts – making sure to leave a good margin of healthy shoot.
- clean your pruners with rubbing alcohol or alcohol hand gel
- burn, or throw in the trash, what you’ve pruned off – don’t leave them on the ground or they can reinfect the tree
Fungicides, such as those containing chlorothalonil, can be sprayed onto the tree in the spring when new needles are emerging in the following years to try to reduce the risk of reinfection (there’s no point in spraying needles that already look infected). But make sure you follow the manufacturer’s instructions.
Cytospora canker disease
Cytospora’s a fungal infection that’s endemic in evergreens worldwide. It causes excessive loss of the inner needles, often sparing the outermost, newest needles. Similarly to sirococcus, it isn’t typically lethal to a tree, but can make it look pretty sad and prevent it from thriving.
The symptoms and treatment are as for pine trees – I’ve written more about identifying and managing cytospora canker here.
Fertilizing cedar trees – does it help?
Yes, fertilizing your cedar tree can help. While anything that weakens your tree increases the chance that it’ll lose more needles than it should AND increase its susceptibility to disease, conversely, having access to appropriate nutrients will strengthen your cedar and bolster its protection.
Fertilizing cedar trees is most important when the tree is young. In any case, once a cedar’s grown large, it’s hard to apply fertilizer to such a wide root area.
In general, I wouldn’t apply fertilizer to a cedar that looks healthy, is a good color, and isn’t losing needles in an unexpected way.
Otherwise, I’d go for a complete evergreen fertilizer, i.e. one containing the three most important components, nitrogen, phosphorus and potassium, or N, P and K. Fertilizers are often labeled with the ratio of these three to each other (the NPK ratio).
I generally recommend Jobes Evergreen Fertilizer Spikes – they have an NPK ratio of 11-3-4; the higher nitrogen content ensures first and foremost that the tree has enough nitrogen to put on new growth.
Make sure you always follow the manufacturer’s instructions – I could write another section on how evergreen can be harmed by excessive fertilizer use!
- Some browning and needle loss from inner branches in late summer/early autumn is normal
- Excessive loss in the above pattern is a sign of stress e.g. from poor drainage, lack of sun or air pollution
- Needle drop in winter or spring is often a sign of winter injury – wind protection and winter watering are key
- If your tree’s been recently planted, it may be overcoming ‘transplant shock’
- Discolored needles with tiny spots indicate it’s a fungal infection
I really hope this article was helpful! Please check out some of my latest articles here – you might find that I can help with some other issues you’ve been experiencing.