- Conifer Topping – It May be Common, But is it Right?
- Rejuvenating conifer hedges
- Lemon Cypress Care: How To Care For Lemon Cypress Outdoors And In The Home
- Browning of Conifer Needles
- Have you recently noticed brown patches on your evergreen trees or hedges? We’ve seen a lot of this damage recently, especially in the Staffordshire and Cheshire area.
- Don’t panic, don’t prune, just keep on reading…
- The reason for most of this damage can be seen best where you have a hedge which is exposed at the top and protected lower down. The brown areas of damage are concentrated at the top…this is where it’s been hit by intense fluctuations in both temperature and winds.
- But don’t despair…have a little patience, and the evergreens will do what they’re best at – continuous growth and repair. The brown needles and shoots will be shed and behind them will come new growth. It may take a while, but your trees and hedges should be able to recover.
- Just a note for anyone who has damage at the base of their hedges rather than at the top (especially alongside roads or footpaths):
- If you have any concerns regarding the health of any of your trees, give us a call and we’ll be happy to talk to you: Get in touch
- Pine Tree Dying Inside Out: Needles Browning In Center Of Pine Trees
- Environmental Causes of Pine Tree Browning
- Pine Needle Fungus
- Pine Trees and Bark Beetles
Conifer Topping – It May be Common, But is it Right?
By John Hushagen
Arborists around the world resoundingly condemn tree topping as a harmful practice that ruins tree structure, makes wounds that the tree can’t close, and destroys the appraised dollar value that trees add to the landscape. Despite this seemingly universal consensus, there is still confusion within the arboricultural community about the topping of conifers.
In theory, topping a healthy conifer with a small diameter cut (less than six inches) should not do significant harm. I have observed that healthy second-growth Douglas firs (Pseudotsuga menziesii) have effectively closed the topping wound with callus after several seasons. Longitudinal dissections in some of the same trees revealed that discoloration and decay were contained to a fairly small area.
However, we must ask how much benefit (e.g., greater safety from “windsail” is to be gained by cutting the top 15 feet off a 135-foot fir. The answer is little, if any.
The goal of conifer pruning should be to reduce the tree’s mass “windsail” without reducing its size. Proper thinning does that.
In practice, most tree toppers don’t stop at a 15-foot reduction and a 4-to-6-inch diameter cut. They prefer to reduce the height of a tree by one-third to one-half. Herein lies the problem. If a 140-foot fir is suddenly turned into a 70-foot fir, this topping cut is probably 12 to 15 inches in diameter. Even the healthiest trees under the best of conditions cannot cover a 12-inch wound. Very often one of the top rot fungi enter the wounded area, rapidly devouring the center of the tree.
As founder and owner of one of the larger tree services in the greater Seattle area, I have had ample opportunity to observe the effects of conifer topping. I once climbed and core sampled in several places an old-growth fir that had been topped many years before by nature or man. The base of the tree was sound, and from the ground it looked healthy. But as I worked my way down from the top, I discovered that there were only two inches of sound wood beneath the bark of a 24-inch diameter trunk, halfway down from the top of the 80-foot tree. The decay column was at least 55 feet long!
Heavy, bushy branches, some covered with fungal fruiting structures, clung to the sides of this grand tree. Halfway down the tree, I stopped coring since it was obvious that the tree was too dangerous to keep. Physiologically the tree’s plumbing was working but structurally it was an accident waiting to happen.
It is not uncommon to find handfuls of gooey, rotten wood below large topping cuts. Rot spreads down the trunk, weakening the attachments of large branches and causing them to break and become dangerous hangers. Some toppers cut back to a lateral branch hoping it will “bend” and form a new top. What usually happens is that these previously shielded branches are too weak to endure the winds they soon encounter.
Upsetting the balance
Topping, or any other form of excessive pruning, upsets the delicate balance among leaf area, shoot growth and root growth. Trees need their leaves to feed shoots, developing buds and roots. Topping starves a tree, forcing it to use its stored reserves to rebuild its crown and fight invading micro-organisms. Topped trees become stressed trees that are susceptible to root rots, a major cause of death in Pacific Northwest trees.
Trees do not blow over because they are “too big.” Shortening trees to make them safer is unprofessional, at best. In many cases, conifer topping could be considered arboricultural malpractice since the “cure” more often becomes “the cause” of hazardous trees. Topping conifers gives us a somewhat shorter tree that rapidly regrows new, bushy tops that are scabbed onto the outside of a rotting trunk. The tree soon becomes more hazardous than ever.
As professionals, we must cease providing services of dubious value to the trees and the customers. Instead, we should concentrate on promoting hazard tree evaluations and proper pruning.
I feel the best way to explain the correct method of pruning a conifer is to say that the goal should be to reduce the mass of the tree without reducing its size. Thinning from the top to the bottom and from the inside out will reduce the tree’s “windsail,” reduce branch weight, remove poorly formed, crowded, broken and dead branches, and allow more light to reach the landscape below.
After this, if the client insists on topping or overthinning, bid the client a good day and walk away with your head held high. You won’t get that quick, short-term paycheck, but neither will you have sacrificed your principles or the long-term welfare of the tree.
Recently, a client who owns one of the oldest homes in Beaux Arts told me that eight large conifers that we had pruned lost no branches in Seattle’s fierce 100-year storm in December 1990. Getting testimonials like that is what quality tree care is all about.
Rejuvenating conifer hedges
Thujas and yews respond well to sever cutting back. Old plants may be reduced by half, and lateral branches should be shortened by half or a third, so as to shape the hedge into a sloping form. Dead branches should be removed. The best time to rejuvenate conifers is summer, from the beginning of June to midsummer. You could also prune in the second half of summer to early winter, however, this period is less favorable. The rejuvenated plants should be looked after, fertilized, and watered in a prolonged dry spell.
Although thujas are an exceptionally die-hard genus, it is only next year that the hedge will start breaking into new growth. Thujas need a lot of sunlight, and they will turn spindly when planted in a shaded position, while yews can take some shade very well. The yew or thuja hedge can be sheared in early spring, or (and) several times during the summer. In order to keep the hedge dense, the tops and the sides of the plants should be trimmed regularly.
In regard to how well conifers take to shearing, junipers fall somewhere in between the yew or the thuja and the conifers of the pine family. While junipers do not take kindly to severe cutting back as thujas would, they respond well to regular trimming, especially Juniperus x media, Juniperus squamata or Juniper virginiana.
One should not even attempt to rejuvenate a hedge of hemlocks, spruces, firs or pines, since these conifers do not break into new growth from old wood. Therefore, it is important that hedges of these conifers should receive regular maintenance right from the beginning. A hedge should be trimmed every year, so as to avoid any die-back of branches. Best time to clip these plants is the summer (June to July), when the weather is warm and dry. Alternatively, pruning could be done in late winter or early spring, but this is less favorable time. Refrain from clipping conifers of these genuses in April and May, after the plants break dormancy, since the conifers will “bleed” too much sap and the wound will take time to heal, which will weaken the plants as a result.
One way of trimming conifers is to nip terminal shoots, leaving only lateral ones. This is an efficient way to keep the hedge in check, albeit one requiring a lot of time and patience. Alternatively, you could cut back young new shoots, which will reduce the growth rate of the hedge, ensuring its compact form and preventing any dead branches. Make sure, that there are still several lateral shoots to cover up the removed terminal shoot. This task is best performed in summer, however, it can be done any other time, provided you do not cut into old wood, and the tree does not loose too much sap. The shoots of pines have no lateral buds, therefore the cut should be made as close to side shoots as possible, so as to prevent dry stumps of cut branches sticking out.
© Giedra Bartas, 2010
Lemon Cypress Care: How To Care For Lemon Cypress Outdoors And In The Home
The lemon cypress tree, also called Goldcrest after its cultivar, is a variety of Monterey cypress. It gets its common name from the powerful strong lemon scent that its branches exude if you brush against them or crush their foliage. You can start growing lemon cypress trees (Cupressus macrocarpa ‘Goldcrest’) indoors or outside. Lemon cypress care is not difficult if you know some basic rules.
Lemon Cypress Trees
Lemon cypress trees come in two sizes: small and smaller. Grown outdoors in their natural habitat, the trees can grow to 16 feet tall. This is quite small for a cypress.
The dwarf lemon cypress (Cupressus macrocarpa ‘Goldcrest Wilma’) is the better choice for a houseplant. This small tree usually does not grow taller than 3 feet, making it perfect for indoor containers. The tree has many admirers, thanks to its green-yellow needle-like foliage, conical growth pattern and bright fresh citrus smell. If you are thinking of growing lemon cypress, you’ll need to understand basic rules of lemon cypress care.
Lemon Cypress Care Outdoors
In general, growing lemon cypress is not difficult. The trees require well-draining soil, but are not picky about whether it is loamy, sandy or chalky. They also accept acidic, neutral or alkaline soil. If you are growing lemon cypress in your backyard, you’ll need to learn about care for lemon cypress outdoors. They thrive in U.S. Department of Agriculture plant hardiness zones 7 through 10. Lemon cypress trees cannot survive shade, so you’ll need to plant your outdoor tree in a sunny spot. And don’t neglect irrigation, especially immediately after planting. During the tree’s first growing season, you’ll need to water twice a week. Watering is always an important part of care for lemon cypress outdoors. After the first year, water whenever the soil is dry. In spring, it’s time to feed the tree. Apply a standard, slow-release 20-20-20 fertilizer before new growth appears in the spring.
Lemon Cypress Houseplant Care
If you decide to start growing lemon cypress trees indoors as houseplants, remember that they do best with cool indoor temperatures. Keep your thermostat in the low 60’s during winter. Perhaps the most difficult part of lemon cypress houseplant care is ensuring sufficient light. Select a window that provides good sunlight and turn the container regularly to give each side a turn. The houseplant requires 6 to 8 hours of direct sun.
Don’t forget water – essential for lemon cypress houseplant care. They won’t forgive you if you don’t give them drenching once a week – you’ll see brown needles appear. Water whenever the soil is dry.
Browning of Conifer Needles
The Plant Disease Clinic has recently received several samples of white pines and other conifers that are turning brown. Many factors may cause browning of conifer needles.
The most common cause of brown needles is winter browning. Evergreen trees continue to produce energy from sunlight (photosynthesize) throughout the winter, which requires water. If these trees do not have sufficient stores of water from the fall to last through the winter, they may dry out and their needles turn brown. Frequent freeze/thaw cycles, cold temperatures, and rapid temperature changes increase the rate of drying. This browning may appear more pronounced on the sunny (south and west) sides of the tree. Winter browning typically becomes visible in late winter or early spring.
It is often recommended that trees be watered intensely once in the fall, right before the ground freezes, to prevent winter browning. Studies have shown that this one watering late in the fall is insufficient to protect trees from winter browning. Trees need the extra water during the dry period of late summer and early fall to prevent drought stress and ensure that they have sufficient water stores to last the winter. Preventing drought stress in late summer is more effective at minimizing winter browning than one watering in the late fall. Brown branches on affected trees should not be pruned off, as they may still have viable buds.
Evergreens near roads may also turn brown in the winter due to exposure to road salts. Some infectious diseases also cause browning of needles. These symptoms usually appear in the spring or summer, although some people do not notice them until winter. Common needle diseases of evergreens include Rhizosphaera needle cast of spruce, Dothistroma needle blight of Austrian pine, and Diplodia tip blight of Austrian and Scots pine.
White pine sample showing browning of needles from winter drying.
Concolor fir tree with brown needles from winter drying.
Evergreen Browning & Needle Drop with Alan Weninger Seasonal needle loss
In spite of being called ‘evergreens’, coniferous trees don’t keep their needles forever. Our local coniferous trees and shrubs include spruce, pine, fir larch, cedar and juniper. The loss of needles on conifers in the fall is normal and natural. This is when coniferous trees shed their oldest needles, the ones located closest to the trunk. This is called seasonal needle loss. The needles turn yellow or brown first, before dropping to the ground. If you take a peek, older evergreens don’t have much in the way of needles in the inside of the tree. Every year a conifer will grow a new set of needles and every year it will lose an old set of needles. A sign that your tree is healthy is when there is new growth in spring at the tips of the branches. No new growth on the tips of the branches indicates the branch or tree is in major trouble.
Needles in coniferous trees have a lifespan which varies depending on the species. Pines, such as white pine or scots pine retain their needles for two to three years, while spruce hold on to their needles for three to five years. In cedars, it’s normal for older branchlets to turn brown. These may stay on the plant for some time before falling off.
The exception is tamarack or larch. While these are coniferous trees, they lose all of their needles in the fall and re-grow fresh needles every spring.
Sometimes needle drop is extreme. What is the cause?
If you think that needle drop in your tree is excessive, and there is no sign of insect or disease problems, then environmental stresses are likely the cause. Extreme needle drop is often the first symptom. Stress symptoms may not appear for two to five years after the stress occurred. For example, if the area flooded around the tree three or four years ago, the damage may not fully show up until this spring.
When a tree exhibits symptoms in its branches or needles, it usually indicates a problem with the root system, specifically the tiny root hairs that are responsible for obtaining water and nutrients. Once a tree is stressed or weakened, it will be vulnerable to insect or diseases. Extreme stress, especially when it damages the root system leads to general decline in trees.
Source of stress
Effect on tree
Adverse temperatures such as extreme winter cold; fluctuating above and below freezing temperatures in mid-winter; and extreme heat in summer.
Winterkill, delayed winter injury, heat stress may cause damage to the cambian layer just beneath the bark. This damage interferes with the uptake of water and nutrients.
Lack of water damages or kills back some of the root system, in particular the tiny and sensitive root hairs.
-overland flooding from extreme weather events,
-a high water table,
-changes to drainage (sump pump outlet or downspout directed at the root zone),
-nearby dugouts or sloughs that are full or overflowing
Prolonged exposure to standing water causes damage to the root hairs of the trees – these are specialized, very fine roots which are responsible for water, nutrient and oxygen uptake in the trees. When these roots are damaged, the trees are not able to pick up enough oxygen which is needed for photosynthesis. This causes the trees to be stressed and the needles to die out much faster than normal.
Salinity caused by high water table, sidewalk salts, road salts, nearby dugouts or sloughs.
Water in the soil that has a high concentration of soluble salts is said to be saline and causes salinity. The salts in the water is toxic to trees, shrubs and other plants.
Soil compaction from construction or heavy equipment; or when trees outgrow a space confined by sidewalks, houses or driveways.
Fifty percent of soil is generally minerals and other materials, 25% is water and 25% is air space.
Compacted soil has very low air spaces. Roots need these spaces for the uptake of water, oxygen and nutrients. Compacted soil also tends to stay wet which causes root rot.
Trees that are planted improperly. (See https://gardening.usask.ca/articles-trees/planting-practices-that-harm-trees-and-shrubs.php)
Most common effect is root girdling which leads to the death of the plant. Same with planting too deep or anything that interferes with or constricts the bark. All of these things interfere with the uptake of water, oxygen and nutrients.
Planting the wrong tree for the existing site conditions.
For example, Colorado Blue Spruce are very sensitive to prolonged exposure to standing water, a leading cause of water stress leading to extreme needle drop. They do best in soils that drain quickly.
If your site tends to be wet, try white spruce (Picea glauca). These are native to the northern boreal forest and naturally grow near streams and rivers.
Note that not all conifers respond the same way to environmental stress. For example, white spruce is native to Saskatchewan and are found throughout the northern parts of the province or near lakes, rivers and streams in the southern part of the province. Jack pines, the least ornamental of the pines, is native to the norther parts of Saskatchewan. Both white spruce and jack pines prefer a moist environment.
On the other hand, Colorado spruce and ponderosa pines are native to the side of a mountain where it is dry with sharp drainage. They are very sensitive to excessively wet soils.
So, will trees with extreme needle drop symptoms survive?
It depends on the cause of the problem and the severity of the symptoms.
For example, if water stress caused by flooding is the cause, the tree may recover provided that there are no large, repeated, long term rain events this year. It may be worth watching the tree for a while – if the buds are alive and new growth occurs, there is some hope. The tiny root hairs will regenerate fairly quickly and the tree will do better if things dry out in the summer.
Similarly, if drought has caused the problem, water your evergreen deeply every week or two at the dripline which is where most of the tiny root hairs are found.
If trees are also showing signs of insect or disease and have few needles, it may not be worth treating if the plant is in severe decline.
I am always a little sad when I have to tell someone that their tree is going to die or that it is already dead. There are certain tree and shrub diseases and some species of insects that have done or will do so much damage to a tree that there is no hope for its survival, regardless of the heroic efforts put forth to save it.
When I get a picture of an evergreen tree that has turned brown, there is usually little hope of it surviving. When a deciduous tree loses its leaves, there is often still hope for its recovery. Deciduous trees have the ability to regenerate new leaves, often within the same growing season. An evergreen tree, on the other hand, does not have that same ability. Once the needles or fronds turn brown, they stay brown. Depending on the cause of the browning, an evergreen may be able to generate new growth from the tips, but sometimes the tree ends up looking like a tree made up of bottle brushes.
Many arborvitae trees succumbed to the drought of 2012. Once that species of evergreen begins to turn brown, there is not much you can do to save it.
We had numerous reports of arborvitaes dying throughout the drought areas in 2012. Unfortunately, there is no amount of tree care that can bring those trees back. The only thing that can be done with those trees is to cut them down.
It can be discouraging to the homeowner to replace the dead trees with new ones. Many times, two or three die in the middle of a row of 15 or 20 plants that have all grown to be about 8 feet tall and the biggest ones you can find as a replacement are only 4 feet high. They will eventually grow up to match the height of the other plants, but it can take many years to do so.
Have you recently noticed brown patches on your evergreen trees or hedges? We’ve seen a lot of this damage recently, especially in the Staffordshire and Cheshire area.
Close-up of Yew needles showing damage
Don’t panic, don’t prune, just keep on reading…
Common Yew showing frost damage/wind scorch
You may not remember much about the weather before ‘The Beast from the East’ arrived in March?
According to the Met Office’s Summaries, both January and February had some rather pleasant spells. This was good growing weather and evergreen trees and hedges responded with new shoots. On the 26th February, I was standing in a field in Devon, admiring some trees, whilst wearing a t-shirt and shorts. Two days later, there was a minimum temperature of -11.7 °C in nearby Hampshire, bitterly cold winds hitting us from north-west Russia and snow over much of the country!
All of those lovely new buds and shoots, plump with potential and ready to burst into growth, suddenly got hit with the worst possible conditions. Below zero temperatures during both day and night accompanied by freezing winds and frosts. All that young growth began to wilt and shrivel.
Add to this the recent spell of dry, very hot weather and you suddenly start to see the damage.
Don’t be tempted to prune it out or ask someone to do it for you. Those plants are under enough stress at the moment! The main thing to remember is that most conifers will not grow back from old wood. So if you prune them now, you could cut back too far and the plant will never recover. If you really want to give nature a helping hand, you could consider applying a general purpose fertiliser. If you’re not sure which one to get, look for one that specifically mentions conifers or evergreens on the packaging (and make sure you follow the instructions for applying it – too much can cause other problems!)
Remember all of the roadsalt, grit and anti-freeze that was thrown around during March’s snowy conditions? It will have been shovelled and splashed by traffic onto the base of your hedge! Excess salt kills all plants – with the obvious exceptions of marine plants like seaweeds!
If the base of your hedge, whether it’s evergreen or not, is looking unhealthy or not coming into bud yet, it may have been damaged by salt and/or anti-freeze. The same goes for roadside trees, especially if they are young or recently planted. Salt damage on trees often shows up as leaves turning brown from the lowest branches working upwards. But if the tree hasn’t come into full leaf yet, this can be difficult to check?!
If you suspect that your hedge or tree has been damaged by salt, the only thing you can do is water it thoroughly, especially in periods of dry weather. This may help to wash the salt into the lower region of the soil where the trees roots won’t have access to it.
Pine Tree Dying Inside Out: Needles Browning In Center Of Pine Trees
Pine trees fill a very specific role in the landscape, serving as year-round shade trees as well as windbreaks and privacy barriers. When your pine trees turn brown from inside out, you may wonder how to save a dying pine tree. The sad truth is that not all pine tree browning can be stopped and many trees die from this condition.
Environmental Causes of Pine Tree Browning
In years of heavy rain or extreme drought, pine trees may brown in response. Browning is often caused by an inability of the pine tree to uptake enough water to keep its needles alive. When moisture is overly abundant and drainage is poor, root rot is often the culprit.
As roots die, you may notice your pine tree dying from the inside out. This is a way for the tree to protect itself from total collapse. Increase drainage and take measures to prevent pines from standing in water — if the tree is young, you may be able to trim the rotted roots away from the plant. Proper watering should allow this condition to correct
itself over time, though the browned needles will never re-green.
If drought is the culprit for needles browning in center of pine trees, increase watering, especially in the fall. Wait until the soil around your pine tree is dry to the touch before watering again, even in the heat of summer. Pines don’t tolerate wet conditions – watering them is a delicate balance.
Pine Needle Fungus
Many types of fungus cause brown banding in the center of needles, but needles browning in the center of pine trees is not always indicative of any particular fungal disease. If you’re certain that your tree is getting the right amount of water and no signs of pests are present, you may be able to save your tree with a broad-spectrum fungicide containing neem oil or copper salts. Always read all directions, since some fungicides can cause discoloration on certain pines.
Pine Trees and Bark Beetles
Bark beetles are insidious beasts that tunnel into trees to lay their eggs; some species may spend most of their lives inside your tree. Usually, they won’t attack trees that aren’t already stressed, so keeping your tree well watered and fertilized is a good prevention. However, if your tree has many small holes bored through branches or the trunk weeps sap or has a sawdust-like material coming from them, it may already be infected. Your pine tree may suddenly collapse, or it may give a warning with droopy, brown needles.
The damage is caused by a combination of bark beetle tunneling activities and the nematodes that ride along with them into the heart of pine trees. If you’re seeing symptoms and signs of bark beetles, it’s already too late. Your tree needs to be removed because it poses a very real safety hazard, especially if branches contain bark beetle galleries. Limb collapse can cause serious damage to anything on the ground below.
As you can see, pine trees turn brown from inside out for a variety of reasons. Pinpointing the most likely cause in your tree is important to keeping it healthy.