Dogwood trees and shrubs can be extremely hardy, not to mention an attractive addition to your landscape adding color and interest to your outdor space year-round.
Depending on the variety or cultivar you go for, dogwood can be quite choosy when it comes to how they are cared for and the environment in which they grow, and any imbalances that occur may lead you to ask the question of how to revive dying dogwood trees and shrubs.
In this article, I’ll be detailing what a problematic Dogwood looks like. This will help you look for clues so you can diagnose issues that are common and what you need to do to fix your ailing tree or shrub. I’ll also be providing tips on how to care for your Dogwood, explaining how you can prevent diseases and pest infestations and generally keep your tree or shrub in tip-top health.
- How To Revive Dying Dogwood Trees And Shrubs
- Dying Dogwood Symptoms and How To Fix
- Caring For Dogwood
How To Revive Dying Dogwood Trees And Shrubs
Reviving a dying dogwood takes a little detective work upfront in order to understand the root cause of the problem so it’s always a good idea to know what these problems look like as well as to understand how to mitigate any potential issues in the first place.
Whilst some trees and shrubs can tolerate far-from-perfect conditions, dogwood does have particular preferences and any deviation can lead to stress. In turn, this stress leads to an unhealthy plant that then becomes far more susceptible to pests and diseases and also the inability to fend off an invasion.
Stress causes all manner of foliar, branch, root, and trunk issues that usually stem from diseases and pest infestations. When left untreated, this can ultimately result in dead dogwood.
So let’s, first of all, dig beneath the surface to understand what ailing Dogwood can look like, what is the most probable cause and exactly what you need to do to save it from dying.
Dying Dogwood Symptoms and How To Fix
Noticing weak, brittle, or dead branches on your dogwood, patches of dead or weeping areas on the trunk, or even a decline in leaf or flower production can be disconcerting and is certainly a cause for concern.
Changes in the health of your dogwood can happen gradually or even suddenly and seemingly without any warning signs so if you have noticed that your dogwood has grown less than the average of one foot in the growing season, then there may be a cause for concern.
Here’s a breakdown of some common dogwood complaints along with what you need to do to fix them.
1) Dying From Bottom Up
The most common reason for a flowering dogwood dying from the bottom up is crown canker. Early signs of this disease include leaves that grow smaller than usual, take on a pale green appearance and may even curl or drop before fall.
As the disease takes hold crown canker can cause twigs and branches to look unhealthy and then break off, especially on just one side of the dogwood.
These symptoms will be accompanied by a dead patch of bark near the base of the trunk that may at first be unnoticed if covered by branches or neighboring foliage. This ‘dead patch’ or canker as it is known will slowly get bigger and eventually encompass the circumference of the trunk, killing the layer of trunk beneath the bark known as the cambium.
Wounds to bark caused by weed whackers, lawnmowers, insects, and animals are usually how this disease gains access to dogwood, eventually destroying the health of the plant and causing death.
If you are lucky enough to spot the canker in its very early stages, then it may be possible to surgically remove it, along with 1-2 inches of healthy bark from the surrounding area. The wound will then need covering to prevent further infection.
If your dogwood cannot be saved, then you’ll need to remove it completely and destroy it. You should also avoid planting new dogwood in the same spot as spores can lay dormant and overwinter in weeds, leaves, and debris that is left behind.
2) Dying From Top Down
If the uppermost areas of foliage on your dogwood begin to wilt, turn brown and crispy or even drop off prior to fall then this is an indication that your plant is getting too much sun.
Dogwood is a sub-canopy plant that needs shade as well as sunshine to thrive so consider moving it to a less sunny spot. Make sure you transplant it into well-draining soil that is enriched with organic matter.
Water it well and be patient as it will need time to recover. Young dogwood, in particular, has shallow roots and needs adequate water. This means you will need to provide supplementary water during the hotter summer months.
3) New Plant Dying After Planting
New dogwood that is showing signs of dying or is dead not long after you have planted it could be a sign that it has either been over-fertilized or is not receiving adequate water.
Avoid fertilizing newly planted dogwood at least for the first year after planting. They need a chance to get established and, in any case, if you have pre-prepared the soil with a good mix of organic matter, this will be enough nutrients at this tender stage in their growth.
I find that the use of fast-acting fertilizers or the overuse of fertilizers can negatively impact a new dogwood and lead to stress or even a dying tree or shrub. If you have been fertilizing a young dogwood, then hold off from any further fertilizing until the following year, when it will have had a chance to develop a well-established root system and has settled in its new environment.
In addition, make sure the soil that your dogwood is planted in remains moist but not soggy. Pay particular attention during spells of hot weather and periods of drought. A new dogwood will need to be watered at least twice per week to ensure it stays hydrated in the earlier stages of its development.
4) Dead Branches
Crown canker is a disease that causes dogwood tree branches to die. This is often a symptom during the more advanced stages after the disease has taken hold.
Other symptoms include slow leaf growth or leaves that drop off and will always be accompanied by a canker on the lower region of the trunk that sometimes goes unnoticed.
Read the section above on crown canker in dogwood and how to tackle this disease.
5) Losing Its Bark
In the more advanced stages of crown canker disease, dogwood can begin to lose bark in the area where the canker itself is located. This is because the canker gradually swells as it grows from the cambium layer of the trunk causing the bark to split and splinter off as the canker below expands.
Another reason for dogwood losing bark could mean an infestation of pests such as the troublesome dogwood borer. These minuscule critters live, eat and also lay eggs in the cambium layer section of the trunk. Signs of their existence include wet patches on the bark that will eventually break off. Read my section above on how to deal with dogwood borer infestations.
Water – either too much or too little – can be a primary cause of wilting dogwood. This is especially true of young trees or shrubs that have recently been planted or those that are positioned in a very sunny spot.
The root system of dogwood, particularly young dogwood is shallow and can cause problems for the effective absorption of water to the remainder of the dogwood tree or shrub. Too much water will swamp the roots and prevent them from getting enough oxygen and too little water will dehydrate the plant.
Making sure you find a spot that receives morning sun and shade in the afternoon, coupled with planting in well-draining soil that is rich in organic matter will help to avoid dogwood wilting. You should also make sure your dogwood is watered at least twice per week when it is newly planted and once per week in dry periods or drought thereafter.
7) Leaves Curling
Noticing curling leaves on your dogwood could be an early sign of powdery mildew. While the most noticeable symptoms are the unattractive white film powder that coats leaves, other tell-tale signs include scorched leaf tips and curled or drooping leaf edges.
Powdery mildew is a fungal disease that usually strikes when humidity is high and there is little wind. To prevent this unsightly although not fatal disease, keep your dogwood sufficiently hydrated in periods of drought and mulch regularly.
8) Leaves Turning Yellow
An early indicator of crown canker can include the yellowing of leaves, early leaf drop, as well as little or no growth during the summer months.
Check the trunk of your dogwood near the base for any signs of canker. If this disease is caught early enough, it is possible to treat. However, detection, once the canker has spread right around the trunk, can be fatal.
9) Not Blooming
Don’t be surprised if your newly planted dogwood doesn’t flower, to begin with. It can take some varieties of dogwood up to ten years to start flowering while others will flower after just a couple of seasons.
Check the general health of your dogwood looking out for any twig or branch deformity, irregular leaf mottling or discoloration, or unusual markings on the bark to identify any potential disease or pest infestation.
If your dogwood looks to be in good health but you are still concerned, it may be worth contacting the nursery you bought your dogwood from to check on the blooming schedule for your particular cultivator or variety of dogwood.
Caring For Dogwood
Providing you afford them the right environmental factors, Dogwood will bring year-round interest to your garden for many years. Here’s everything you need to know about keeping your specimen in the best possible shape and how to save a dying Dogwood when things are going wrong.
Check Soil Moisture
Dogwood is relatively thirsty so ensuring yours is getting enough water by regularly checking soil moisture is critical to a happy and healthy tree or shrub. Soil should be moist but not soggy. This will help to keep roots hydrated and also ensure they receive enough oxygen.
All varieties of dogwood especially newly planted and young trees and shrubs need additional watering during the warmer months. Water newly planted dogwood at least once per week to help their roots get established in their new surroundings. They need one inch of water each week to really kickstart a healthy growth pattern during their first year or growth.
Established dogwood needs up to 6 inches of water each week so supplementing extra water during the hotter months of summer and fall, and making sure you water once or twice each week is essential.
Aim to regularly check the moisture levels in the soil around your dogwood and water if it feels dry 2-3 inches below the surface.
To retain moisture and also add nutrients to the soil, dogwood will benefit from annual mulching. Begin mulching straight after planting by putting a 4-inch layer of mulch around the base. Avoid piling mulch too high around the trunk as this can encourage disease or rot.
White or pink flowering dogwood trees will produce bigger and better blooms if planted in well-composted fertile soil with good drainage. If your garden has clay soil you’ll need to amend it with a mix of sand and plenty of compost or at the very least, plant your dogwood halfway up a slight slope to improve the drainage.
Most dogwood shrubs will tolerate damp conditions – provided it is rich in organic matter – and so drainage is less of a consideration. If conditions are damp or even wet for long periods of the year, make sure your dogwood shrubs are planted in an area that gets a decent amount of sun for a good proportion of the day.
Check Soil Ph
All dogwood whether trees, shrubs, or creeping varieties, prefer soil with a pH range of between 5.0 to 7.0. This means the soil needs to be slightly acidic, bordering on alkaline.
Check the soil pH with a soil test kit before planting and amend where necessary to get the right pH balance. Use lime or wood ash to increase alkalinity (raise soil pH) and mulch or add compost if you need to increase acidity (lower soil pH).
For optimal growing success across the spectrum of dogwood species aim for soil that is well-draining but remains slightly moist and is also combined with a good deal of organic matter.
Soil Ph Test Kit
There are few things less annoying in gardening than realizing that your soil needs amending after you have planted. Digging in soil amenders after you have newly planted or needing to dig it up and replant can be time-consuming and costly. In both cases you risk causing stress to the new planting.
I find that using a soil pH test kit before you plant is a quick and easy way to assess the pH in your soil. They are relatively inexpensive to buy and will save you time and money in the long run.
Dogwood prefers fertile soil, which they need to continually absorb a range of macro and micronutrients steadily and naturally throughout the seasons. Dig in compost to the soil around your dogwood annually and to coincide with any other soil amendment that needs to take place.
In addition, place a good 3–4-inch layer of mulch around the base of your trees or shrubs in the fall. Both help to enrich the soil with nutrients and also help to enhance the level of acid needed to support healthy growth.
You can also ‘top-up’ the range of macro and micronutrients in your soil by fertilizing your dogwood periodically.
Typically, dogwood is a light feeder and so an annual slow-release fertilizer such as Espoma Holly Tone Organic Fertilizer added in spring at the start of the growing season should be sufficient.
This will be enough to support a healthy root system as well as new growth.
Sunlight And Position
Dogwood grows naturally as a sub-canopy plant on the edge of forests where a portion of their day is in sun and the other is covered by shade. Dogwood that is exposed to too much sun can suffer scorched leaves and will also need a serious amount of watering to keep hydrated, especially during the warmer months.
In contrast, a dogwood that does not receive enough sunlight will bloom less or worse still, not bloom at all.
3-4 hours of morning sun is ideal for most species of dogwood, especially the more hardy varieties. This will ensure that they receive adequate sunlight without getting scorched and avoid soil becoming too dry from intense bursts of heat.
Treatment For Pests & Diseases
Unless you have a cultivar that is resistant to disease, you are going to need to keep your dogwood happy and healthy to avoid all manner of diseases and pests that are known to attack these plants, especially if they are stressed or not cared for adequately.
The most common fungal disease known to affect dogwood is anthracnose.
This fungus will attack leaves first where tiny white spots with reddish/purple edges (known as Spot anthracnose) begin to show. Leaf edges will also turn light brown.
If left untreated the fungus will cause cankers which, according to USDA Forestry Services, first signs usually appear in the lower crown on smaller branches and gradually extend to larger branches and ultimately spread to the trunk.
Not only are cankers unsightly with their weeping lesions and dead patches, but if left untreated or unnoticed, they will also kill your dogwood within 2-3 years.
Anthracnose favors the rainy season where conditions are moist and warm.
Treat anthracnose as soon as you see it by pruning any part of your dogwood that shows signs of infection. Destroy the infected parts that you remove rather than composting them and check for signs of the fungus on neighboring trees and shrubs. If you are unlucky enough for the anthracnose to have spread to other plants in your garden, these will need to be pruned too.
There are fungicides that can be sprayed on the affected areas. These are most often chemical-based and can be toxic not only to pets but also, to other wildlife in your garden such as the earthworms and microbes that live in the soil around your dogwood.
To help avoid an attack of anthracnose on your dogwood you should aim to maintain a fertile rich soil by composting and mulching. Make sure soil is well-draining so that excess water can be carried away during the rainy season.
Septoria leaf spot
Septoria leaf spot is another fungus common to dogwood with symptoms similar to those of anthracnose.
This disease is most noticeable in summer. Leaves appear with small, brown, slits or lesions and leaf edges are bordered with a dark reddish/brown color. This fungus first appears when conditions are warm and humid and can cause leaves to turn yellow and drop early. All other areas of the dogwood are unaffected.
Whilst not as serious as anthracnose, an untreated dogwood can eventually become weakened and therefore more prone to other health issues and stress.
Septoria can remain dormant on dropped leaves and spread via spores that can be carried on the wind so always rake fallen leaves away to prevent the spread into the following year.
There are a number of fungicides available to buy that can be sprayed onto new buds at the start of the growing season. Many fungicide products that are used to treat fungus diseases on dogwood contain copper that, if used repeatedly, can cause a toxic build-up in the soil. This is particularly dangerous for earthworms and other microbes found in soil so always exercise caution and read the label before using.
Powdery Mildew On Dogwood
This fungal disease usually occurs in the heat of summer when humidity levels are high and there is little wind. Symptoms appear as a rather unattractive white powder over leaves that can then cause them to develop red or purple blotches.
Other tell-tale signs include scorched-looking leaf tips and/or curled or drooping edges. Leaves can also begin to drop off in the height of summer.
Young dogwood can be particularly susceptible to powdery mildew and whilst it is unlikely to kill the plant, it does cause stress and can make it more prone to other pests and diseases.
Prevention is often more effective than cure when it comes to powdery mildew on dogwood. Regular mulching, slow-release fertilizers, and keeping your dogwood hydrated without overwatering will all help to alleviate the onset.
Fungicide sprays can also be applied when the first signs of the fungus appear, and you should always refer to the manufacturer’s instructions when using to avoid potential hazards from using chemical-based products that can be dangerous to people and pets.
Root rot in Dogwood
A consequence of not planting dogwood in well-draining soil can result in root rot. This is where the roots are allowed to remain soggy and are left to stand in water for prolonged periods of time. The outcome leads to roots that are starved of oxygen, and rotten roots, and often this causes irreversible damage.
Root rot can be difficult to detect initially as the problem begins below soil level. In the later stages of root rot, visible signs include wilting leaves and branches and also leaf tips and edges that have turned brown. It can often be too late to reserve the damage caused when root rot gets to this stage.
Crown canker or collar rot is a disease that causes stress and damage to flowering varieties of dogwood and is possibly the biggest threat to the longevity of dogwood if the disease is allowed to take hold.
Early signs of crown canker include little or no growth during the summer months and less than-average leaf growth or production. Yellowing of leaves and/or leaf drop can also occur before fall and your dogwood may appear slightly droopy and generally unwell.
The biggest cause for concern is where a growth-like swell or sore (known as a canker) appears near the base (crown) of the trunk close to ground level. Often this canker will split the bark to expose the wood beneath and a thick, dark liquid will ooze out.
Whilst it is possible to remove the canker along with 2 inches of healthy surrounding bark as a method of preventing the spread of the disease, this operation in itself can leave your dogwood exposed to other infections or stress or a potential infestation of the common pest – dogwood borer. Mitigating the risk of infection and infestation can be achieved by painting the wound left by the removed canker with a protective layer of asphalt-based wound paint.
Again, prevention of crown canker by selecting a variety of dogwood that suits your climate, soil conditions, and planting position is often better than a cure. In addition, when mulching, be sure to avoid covering the base of your dogwood. This will reduce the risk of any potential disease penetrating the trunk, to begin with.
Pests on Dogwood
There are a number of pests that can cause debilitating damage, unsightly blemishes, and often death to dogwood. The dogwood borer, for example, wreaks havoc by laying its eggs in the section of the trunk just beneath the bark (known as the cambium layer) and subsequently restricting the absorption of nutrients and water that can eventually cause branches to die.
Other scale insects such as the dogwood sawfly can – in large colonies – decimate foliage while the dogwood club gall midge causes tubular-shaped swellings on the tips of twigs. At best, infected twigs can die, and at worst, twigs become deformed.
Pesticides are often recommended to curb the infestation, and this should be administered with caution just before leaf buds begin to break. Often though, if an infestation has taken hold over a number of years, the best option is to cut back all infected branches.
In addition, since the pests will often overwinter on fallen leaves, always rake thoroughly and never place them on your compost heap.
Treat With Insecticide
The type of pest infestation your dogwood has will determine which insecticide is best and where to spray it on your tree or shrub.
Dogwood borers will commence activity from spring onwards and treatment with insecticide should coincide with this. Insecticide applications will need to be made to the base of the trunk and to any wounds on the bark. Subsequent applications will need to be made every 2-3 weeks until the infestation subsides.
For infestations such as dogwood sawfly or dogwood club gall midges, the best time to use insecticides is when you can see them moving on leaves or twigs respectively. This usually occurs at the start of the growing season however, you’ll need to keep a watchful eye throughout spring, summer, and even into fall as new insects are hatched and a new generation takes hold.
After the first application, insecticide treatment can continue every 10-14 days until all signs of infestation have disappeared. Always read the manufacturer’s instructions when handling and using insecticides since most are toxic to people and to pets.
Pruning Diseased Wood
Mature dogwood can be extremely hardy and likely to produce more vigorous healthy and colorful stem growth after hard pruning. In fact, regular pruning whether that be to clear away dead or diseased branches and leaves or purely for aesthetic reasons is good practice and should be undertaken regularly for dogwood trees and shrubs.
Pruning healthy dogwood should be done before any new leaf growth begins to show and typically, this is from late winter to mid-spring.
Diseased dogwood, however, should be dealt with differently, whereby damaged or decayed branches and stems should be removed on the first site as this will help to limit the further spread of infection from fungus or pests.
The downside of pruning dogwood outside of its period of dormancy can mean that it may experience weaker regrowth in the following season. This is because whilst it is actively growing, its energy reserves are powering leaf growth which can be subsequently lost if pruned away. In wintertime, when your plant is not actively growing, these energy reserves are concentrated in the roots and therefore not lost by any pruning activity.
When pruning, always make clean diagonal cuts at least 2-3 inches clear of any diseased or decayed branches. Use sharp cutters, a saw, or a pruning knife that has been thoroughly sterilized before use, and always re-sanitize after each cut to minimize the risk or spread of further disease or infection.
To mitigate the risk of future disease, try to keep dogwood trees and shrubs healthy by regular mulching, adequate watering, and ensuring the soil in which your dogwood is planted is well-draining and enriched with organic matter.
It’s also a good idea to minimize damage to the base or trunk of your dogwood by avoiding getting your lawnmower, strimmer, or weed whacker too close.
In addition, rake away and dispose of dead or decayed fallen leaves regularly and mulch around the base of your dogwood annually making sure to avoid piling up mulch too close to the base.