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Archive for the ‘Interesting gardening trivia’ Category

White pine shedding 1-year old needles

White pine needle sheddingI have been noticing a lot of yellowing needles on the pine trees in our area this fall and it reminded me of the blog post I published in the fall of 2012.

When a large number of pine needles start to turn yellow then drop, homeowners can become quite concerned and this may be one of those years when needle drop, especially in white pines, is especially noticeable.

It’s important to understand that this doesn’t necessarily mean you have a disease or insect problem.

Read on …

From October 17, 2012 …

 

Help! A lot of the needles on my pine tree are turning brown and falling off. What’s going on? Should I be worried? Is my tree dying?

White pines shed the previous year's needles each fall.

White pines shed the previous
year’s needles each fall.

We often get questions like this in the fall. The keyword here is “fall”. Everyone is used to the deciduous trees coloring up and dropping their leaves in the fall but many are not aware that pines and many other evergreens also go through a natural “leaf” drop at this time of the year.

But they’re evergreens! They’re not supposed to lose their needles.

The difference is that evergreens don’t drop all of their “leaves” at one time like deciduous trees and shrubs do so it normally goes unnoticed.
Every year all evergreens, including the broadleaf evergreens, shed at least some of their older foliage. When this leaf or needle drop occurs and how much is shed depends upon the species.

Since we aren’t accustomed to thinking of fall needle drop as being a normal occurrence for pines and other evergreens, many people automatically assume that they have an insect or disease problem when this happens. They’re quite relieved to find out that it’s normal.

1-year old growth drops it's needles while the current season's growth remains green.

1-year old growth drops it’s needles while
the current season’s growth remains green.

Pines as a group shed their oldest needles in the fall. Most pines keep their needles for 3 to 5 years spreading out the needle drop over that period. White pines, on the other hand, hold their needles for only one year. Because of this, in certain years, the needle drop on white pines can be rather dramatic. This seems to be one of those years. At least in our area of the Shenandoah Valley, the white pines seem to be full of yellowing needles and this can be a bit alarming to a homeowner.

Why do you notice this in white pines especially?

White pine needles turn yellow then brown before they drop

White pine needles turn yellow then
brown before they drop in the fall.

It’s because, since they only hold their needles for one year, variations in growth rate from one year to the next can have an effect on the percentage of needles that are shed in a given fall. When you look carefully at white pine branches in the fall, you should see that the needles at the ends of the branches (the current year’s growth) are healthy and green and that the one year old needles behind them towards the interior of the tree are the ones that are yellowing and turning brown. Eventually these will be shed.

When environmental conditions favor good, strong spring growth, the lush, new foliage will usually hide the shedding needles behind it. In these years, the natural needle drop in the fall is less obvious.

Browning needles on the one-year old white pine growth

Last year’s needles have turned brown.

However, if new growth in the spring is slowed due to drought for instance, this growth will be shorter and will produce fewer needles than the previous year’s growth (assuming a normal growing season in that year). This sometimes means that a higher percentage of the needles on the tree are one year old needles and when these needles begin to turn yellow and brown in the fall, it becomes much more noticeable (especially if there was a good growing season the year before).

This seems to be the situation for us this year. During the time when new growth was forming on the white pines, our temperatures were above normal but rainfall was well below normal. This resulted in reduced spring growth and consequently, it’s possible that more needles may be shed this fall than are retained on the tree. Interesting, huh?

So now you know and you can rest assured that your white pines are probably not sick or insect infested – they are just shedding … naturally!

Until next time – Happy Gardening!

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Autumn olive

This was the title of a question posted on our Discussion Board several weeks ago. Here is the post:

Autumn olive

Autumn olive in fall

What is the name of the invasive species of small bush/tree with thousands of little red berries, and is spreading like kudzu? It grows two or three inches a day seems like, and is dominating every hedge row in my area. I live near Stuart, Virginia. What is the best way to eradicate them?

My guess was autumn olive but I asked for some additional information to be sure of the identification:

The silvery undersides of the autumn olive leaves

The silvery undersides and
alternate arrangement of 
autumn olive leaves

Are the undersides of the leaves silvery in color and are the leaves arranged alternately on the branches? If the leaves are arranged opposite each other on the branches and the leaves are green, then it would be a bush honeysuckle. In either case, they are both invasive and hard to control.

He replied back that the leaves were silvery underneath and they were arranged in an alternate pattern on the stem.

Autumn Olive – as I suspected.

Autumn olive (Elaeagnus umbellata) is a deciduous shrub that is native to China, Japan, and Korea. It was introduced to the United States in 1830 as a fast growing shrub that could be used to quickly revegetate disturbed areas and provide erosion control as well as habitat and food for wildlife. It certainly did the job but unfortunately did it so well that the shrub has now become invasive in much of the eastern and central US.

Pale yellow autumn olive flowers

Pale yellow autumn olive flowers

Autumn olive is very prolific and is as happy growing on dry, rocky, infertile slopes as it is growing in rich garden soil. It is drought tolerant, salt tolerant, and even grows in very acidic soil.

This is one tough plant!

One of the reasons that autumn olive is able to thrive in nutrient-poor soils is its ability to produce its own nitrogen with nitrogen-fixing root nodules. This can become a problem for many of the native species that are adapted to areas with infertile soil because it interferes with the natural nutrient cycle.

In addition, because of its vigorous growth and quick spreading habit, autumn olive can easily outcompete and displace these native plants.

Autumn olive laden with fruit

Autumn olive laden with fruit

The other problem is that these shrubs produce a tremendous number of small red fruits all along their branches and each of these contains a seed. Birds and other animals apparently scarf up the fruit and are responsible for dispersing the seeds far and wide!

Autumn olive fruit contains a lot of lycopene and is apparently quite tasty when it is perfectly ripe. Before that time, it has a very bitter taste due to high levels of tannin – similar to unripe persimmon fruit. The few that I tried the other day, though deep red in color, really made me pucker up! Definitely not ripe yet! The tannin content decreases as the fruit ripens and it becomes sweeter. If you look online, you can find quite a few recipes which use autumn olive fruit to make jam, juice, and other things!

BUT …

These shrubs ARE invasive and efforts should be made to control them. However, this is no easy task! If you cut them down or burn them, they quickly sprout vigorous new growth from the base. Seedlings pop up everywhere the fruit/seeds drop.

Deep red fruit is speckled with silvery scales

The deep red fruit of autumn olive is
speckled with silvery scales

Seedlings can be hand pulled but it is best to do this when the ground is moist so you increase the chances of removing the entire root.

Seedlings and young shrubs can be controlled by spraying the foliage with triclopyr (found in many brush killers) or glyphosate (the active ingredient in Roundup) according to the label directions.

Large, mature shrubs are harder to kill. One of the best methods is to cut them down and then immediately apply an herbicide containing glyphosate or triclopyr directly to the freshly cut stump according to the label directions for stump treatment. You can use a paint brush or a spray bottle to apply the herbicide and if you add a dye to the mix, you can easily see when you have good coverage on the stump.

One of the best times to do this is in the early fall before the fruit (with seeds!) matures. At this time, the plants are beginning to prepare for winter by moving nutrients and stored starches from their leaves into their roots. Spraying systemic herbicides at this time (for any perennial weed) means that these chemicals get transported down to the roots more quickly thereby increasing their efficacy.

Good luck if you have this stuff! It is growing in dense thickets around our little orchard and every year it seems to close in a bit more!

Until next time – Happy Gardening!

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The rhododendron bald at Craggy Gardens

A few weeks ago, Eric and I took a trip down the Blue Ridge Parkway. We tried to time our trip to coincide with the rhododendron bloom in the North Carolina mountains, specifically at Craggy Gardens on the parkway just north of Asheville. While the native rhododendrons, Rhododendron catawbiense, were just beginning to show some color, the flame azaleas and mountain laurel were in full bloom. It was beautiful!

Mountain laurel in full bloom.

Mountain laurel in full bloom.

Azalea gall on native flame azalea

Azalea gall on native flame azalea

When we stopped to take some pictures, we noticed that a few of the azaleas had some strange growths on them that looked like some type of gall. It turns out that this was the azalea gall which is quite common on both native and hybrid azaleas. Catawba rhododendron is also quite susceptible. In fact, the majority of the rhododendrons growing on the rhododendron bald above the Craggy Gardens Visitor Center had at least a few of these unusual, fleshy galls.

I’ve written about galls on plants before but most of those I have talked about were galls that developed in response to insect activity.

Azalea gall has caused swelling and distortion of young leaf tissue of this native rhododendron

Azalea gall has caused swelling
and distortion of young leaf tissue
of this native rhododendron

The azalea gall, Exobasidium vaccinii, is caused by a fungus which infects the leaves, flowers, and branch tips of azaleas, rhododendron, and certain species of Vaccinium like blueberries and cranberries.

The fungus causes abnormal growth in the tissues that are infected. These swollen tissues form the gall and cause distortion of the leaves, stems, or flowers.

Azalea galls can be light green, pinkish, or (as we most often observed) white.

This pale green gall will become white once the spore layer forms

This pale green gall will become
white once the spore layer forms

During the late spring and early summer, a white spore layer forms on the surface of the gall. This may be why all the ones we saw were white. These spores are dispersed by wind or rain to healthy leaves or flower buds on the same or different susceptible plants. The fungus remains dormant in these tissues until the following spring when new galls form soon after the plant begins to grow. Once the spores are released, the gall begins to turn brown and eventually dries up and falls to the ground.

Cool, wet weather favors the dispersal of the fungal spores. Up on the ridge tops of the Blue Ridge Mountains where native rhododendron and azalea are prevalent, fog and misty rains are common in the spring and summer. These conditions are perfect for the spread of this disease.

The rhododendron bald at Craggy Gardens is enveloped in a misty fog

The rhododendron bald at Craggy Gardens is enveloped in a misty fog

A rhododendron flower is completely distorted by a gall

A rhododendron flower is
completely distorted by a gall

Though the azalea galls may look harmful, normally, they do not have an adverse effect on the plants. However, if cool, wet weather persists during the time of spore dispersal, the disease can spread more readily and result in the formation of many more galls the following spring. This can sometimes have a negative effect on the health and vigor of the plant.

Usually only a portion of the flower head is affected.

Often only part of the flower head
is affected by the gall.

Azalea gall is a common problem in many hybrid azaleas. Physical removal of galls is the simplest control method. Galls should be pruned out with shears before the white spore layer forms.

If galls are prevalent or conditions are favorable for the spread of the disease, fungicide applications may be warranted. Bonide Fung-onil or Bonide Mancozeb can be applied according to the label directions to control azalea leaf and flower gall. Begin applications just prior to bud break in the spring.

Until next time – Happy Gardening!

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Male oak catkins dangle from oak branches

Mature oaks usually retain leaves only on their lower branches.

Swelling buds in the spring pop
off marcescent leaves.

Spring has been slow to come to the Shenandoah Valley this year. It has been cold and windy for days; not feeling very spring-like despite what the calendar says.

Regardless of the chilly temps, I have observed the steady progression of the season in the trees surrounding our house. A few weeks ago, I noticed that the oaks had finally shed the last of their marcescent leaves as the buds began to swell. Soon after, the male oak flowers started to appear.

Oak trees produce separate male and female flowers on the same tree.

The male flowers develop first just as the tiny leaves begin to form. These conspicuous flowers are long, yellow catkins that dangle down from the tips of the branches.

Tiny staminate flowers arranged along a central stem make up the catkin.

Tiny staminate flowers arranged along
a central stem make up the catkin.

Pollen from these flowers blows through air to pollinate female flowers on nearby trees. Oak pollen is produced in copious amounts and can cause real problems for those that are allergic to tree pollen. Since the catkins shed their pollen before the leaves are fully expanded, the pollen is able to drift relatively unimpeded through the air to reach the female flowers.

The female oak flowers are much less obvious and in fact are seldom seen because they are very small and generally found on the tips of branches higher up in the tree. If pollinated, the female flowers will give rise to acorns – eventually.

Female oak flowers are quite inconspicuous

Female oak flowers are quite
inconspicuous. Red oak shown here

Oaks are broadly divided into two main groups; the red oak (or black oak) group and the white oak group.

In general, trees in the red oak group have pointed lobed leaves and trees in the white oak group have rounded lobed leaves.

Acorn development is different between these two groups. Acorns in the white oak group are sweet and palatable and mature in one season. It takes two years for acorns in the red oak group to mature; so in the fall, you may notice tiny one-year old acorns as well as the larger two-year old acorns on the same tree. Red oak acorns are very bitter tasting.

Red oaks as a group generally flower earlier that the white oak group. Our mature red oaks have thousands of catkins hanging off the branches right now while the white oaks, which include the chestnut oaks, are just beginning to bud out.

Acorn production can be affected by certain weather conditions that disrupt flowering or hinder pollination.

Oaks rely on wind rather than insects for pollination. If the weather is misty and rainy during the time that the oak pollen is being shed, the pollen can be washed right out of the air. This can limit pollination and reduce the acorn production for that year. Freezing temperatures in the spring can kill the flowers and also reduce the acorn crop.

Dried up catkins and some yellow oak pollen litter the deck

Dried up catkins and some
yellow oak pollen litter the deck

In a good year (for the oaks, that is), the yellow oak pollen billows from the trees on the slightest of breezes. Some of it will reach female flowers on adjacent oaks but it seems that most of it just settles to the ground.

So far, not much pollen has been released; it can be up to two weeks after the male flowers first appear before pollen is shed.

I know the pollen clouds are coming and once they do, everything outside will be covered with a fine yellow dust!

Once their pollen is shed, the catkins dry up and drop from the tree. The ground under the trees becomes littered with these spent flowers.

Coming up - the pine pollen!

Coming up – the pine pollen!

We find them all over the deck, on the roof, in the gutters, on the cars …

Just yesterday, I noticed that the male cones on the tips of the pine branches have begun to develop. More pollen is on the way!

Until next time –

Happy Gardening!

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Grafted melon at Merrick Farm, Wilbraham, MA. Photo: Megan Poljacik

When I first heard about grafted tomato plants several years ago, I thought the idea was crazy. I was very aware of the great cultural benefits of grafted trees and shrubs but why in the world would you spend the time and effort to graft a vegetable that only grows for a season then dies with the first frost?

Grafted tomato

Grafted tomato; Cornell University Cooperative Extension

It didn’t dawn on me at the time that the same disease resistance and increased overall vigor that the rootstock imparts to a grafted fruit tree could also work for a grafted tomato plant. When you think about it, this is a brilliant concept because tomatoes and many other vegetable crops have a plethora of disease and pest problems that we as gardeners are constantly battling.

It turns out that grafting vegetables is not a new practice at all – they’ve been doing it in Asia for a long time!

What is grafting?

Grafting involves taking the top of a plant (the scion) that has very desirable fruit qualities like superior taste (but low vigor and disease resistance) and attaching it to the bottom of a plant (the rootstock) that is known for its vigorous growth and disease resistance.

Getting ready to graft a melon (scion) to a gourd rootstock at Merrick Farm, Wilbraham, MA

Getting ready to graft a melon (scion)
to a gourd rootstock at Merrick Farm,
Wilbraham, MA  Photo: Megan Poljacik

One of the main advantages of grafted vegetables is their resistance to soil-borne pests and diseases.

Remember my whole diatribe on crop rotation? There are a lot of people with small backyard gardens that don’t have the space to rotate their crops. Planting grafted vegetables reduces the need for crop rotation. The rootstock that is used for the graft is selected for its resistance to a wide range of soil-borne diseases, including those that persist in the soil for many years. So even if diseases like Verticillium wilt, Fusaruim, bacterial wilt, or tobacco mosaic virus are lurking in your soil, grafted tomatoes are less likely to be affected because of their vigorous, disease resistant rootstock. You have a super plant!

Completed melon graft; Merrick Farm, photo: Megan Poljacik

Completed melon graft; Merrick Farm, photo: Megan Poljacik

What about diseases like early blight and late blight that travel to the plants via wind and rain? Are grafted plants protected from these devastating diseases? Unfortunately, these diseases attack the above ground parts of the plants – the foliage, stems, and fruit and the rootstock of grafted plants cannot directly provide resistance to these foliar diseases. However, as I have said many times before, healthy, vigorous plants are much less susceptible to disease and pest pressure.

An heirloom tomato grafted on a superior rootstock will theoretically be more vigorous, healthy, and productive than if it were growing on its own roots. The root system of the “super rootstock” will be much more extensive, thus providing more surface area for absorption of water and nutrients. This should lead to a healthier plant. Many of the grafted tomatoes that you will find are heirloom varieties. These very tasty tomatoes can be more prone to disease problems than hybrid tomatoes so grafting may offer a healthier, more productive plant.

Conversely, if a blight resistant tomato such as Defiant is grafted onto a hearty, disease resistant rootstock, you could end up with a seriously disease resistant tomato! Actually, this is a popular grafted tomato that is available!

Tips for growing grafted tomatoes

Grafted tomato planted with the graft well above the soil line.

Grafted tomato planted with the graft well above the soil line.

Remember how you have always been told to plant your tomatoes as deeply as possible because they will develop roots all along the buried stem and you will end up with a more robust plant? Deep planting is a no-no for grafted plants. It is extremely important to keep the graft above the soil line when you plant. If the graft ends up below ground, roots will develop above the graft, which totally defeats the purpose of having a grafted plant! When the scion roots into the soil, the disease resistance of the rootstock is bypassed and the plant is no longer protected. Money wasted! This may be the reason why some people are not successful with grafted plants and feel that they are not worth the expense to purchase.

Keep the graft at least an inch above the soil when you plant.

As the plant grows, provide it with a good support system to keep it off the ground. Any stems or branches that touch the ground can take root – again, bypassing the disease resistance of the rootstock. We grow our tomatoes on a trellis and keep all the side shoots tied up as well as the main stem. You can also tie them to stakes or a fence or grow them in cages – anything that keeps the plant from sprawling on the ground where it can take root.

It is also important to remove any growth that develops below the graft.

Many different vegetables are being grafted these days.

Melons are commonly grafted to improve disease resistance and yield.

Melons are commonly grafted to improve disease resistance and yield.

Although tomatoes are the most common, you can also find (or create your own) grafted peppers, eggplants, cucumbers, squash, melons, and watermelons. Each of these is grafted onto vigorous rootstocks that are developed specifically for that particular vegetable type and the specific diseases that attack it.

Grafted vegetables not only have increased vigor and resistance to soil-borne diseases but, because of the superior root system that develops in these plants, they also show an increased tolerance to environmental stresses like drought, temperature extremes, and nutrient deficiencies. The extensive root system increases the area that the plant can exploit for the water and nutrients needed for growth. The result is a healthier plant that not only bears well, but potentially requires less fertilizer, is drought tolerant, and has a reduced need for pesticide applications.

This may be the year that we give grafted plants a try. We may try to pick up a tomato plant or two at a local garden center. It will be especially interesting if we can find a grafted version of one of the varieties that I plan to grow from seed. That would be a cool experiment! I will keep you posted!

Until next time – Happy Gardening!

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A heavy snow shower blows into the valley on saturday creating near whiteout conditions. Photo taken by Melissa Jones.

A heavy snow squall with high winds blows into the valley on Saturday afternoon
briefly creating near whiteout conditions. Photo taken by Melissa Jones.

It’s very cold – for us, that is.

The high temperature for Fishersville, VA was only 11°F today. The low tonight is supposed to be four below with a wind chill of -8! Everyone in New England is probably laughing at me – considering this to be a heat wave compared to what they have been experiencing during this very cold winter.

Helleborus foetidus with its green bell-shaped flowers pokes up out of the snow.

Helleborus foetidus with its bright green
bell flowers pokes out of the snow.

Luckily, we have a bit of snow to insulate our plants during this frigid cold snap. It isn’t as much as we had hoped, but it will help. I know the vineyards in the area were hoping for at least a foot during this last storm. With the extreme cold that is now upon us, they were hoping to have a good snow cover to protect the grape vines. Unfortunately for them, the storm didn’t pan out as predicted. This was a light, fluffy snow that came down in fine, tiny flakes and accumulated very slowly. The totals in most places fell way below the 8″-12″ that was predicted. We only got 4.5″ at our house – but still, it was beautiful and it will provide some protection for the plants in our gardens.

Begonia grandis seed heads have already dropped their seed. Daffodil foliage pokes up in the background.

Begonia grandis seed heads. Daffodil
foliage pokes up in the background.

Snow has excellent insulating properties, especially when it is at least 10″ deep. The temperature under a deep snow pack is generally around 32 degrees even when the air temperature is below zero! I suppose this might be some consolation for those New Englanders who are buried under several feet of snow. They certainly have been hammered up there! Of course, with that much snow, many shrubs could be pretty flattened by the spring thaw! Here are some tips to help with that when the time comes.

Buddleia sprouts from roots.

This Buddleia died back completely
but came up from the roots.

Frigid temperatures without any snow cover can be very damaging to some of the trees and shrubs in the landscape. Those that are marginally hardy where you live are especially susceptible to winter damage and winter kill. I expect that there may be a lot of winter dieback on crape myrtles and butterfly bushes in our area after this winter. Get your pruning shears and pruning saw ready! Hopefully the roots will be protected underground. If the roots survive, new growth should pop up from below to form a new plant.

Luckily, the wind chill does NOT affect plants; only the actual air temperature. Wind chill only affects warm-blooded animals like us and our pets, farm animals, even the wild creatures like birds and mammals; critters that are trying to maintain a constant body temperature.

Winter burn on Nandina

Winter burn on this Nandina.

This is not to say that winter winds don’t affect our plants. What can harm the plants are the drying effects of the wind. The air in winter is very dry, as evidenced by our dry skin, chapped lips, and static electricity shocks! When the wind blows this cold, dry air over the plants, it carries precious moisture away from the surface of the plants. Evergreens, both broadleaf and needled, are especially affected because they continually lose water through their leaves during the winter; the wind accelerates moisture loss. When the soil is frozen or dry, it is hard for the plant to replace this water by uptake through the roots. This can result in winter damage and winter burn to leaves and even whole branches.

Rhododendron with tightly curled leaves. The flower bud is protected but heavy bud scales.

Rhododendron with tightly curled
leaves. The flower bud is protected by
heavy bud scales.

Rhododendron leaves droop down and curl up tight like little cigars when it is extremely cold. This is a reaction to the cold temperatures but there is still a debate as to why they curl. Read more about it – it’s pretty interesting!

One way to help protect your evergreens from wind burn and winter damage is to spray them with an anti-desiccant like Bonide Wilt Stop. Wilt Stop protects evergreens from winter injury by forming a soft, clear flexible film over the leaves. Wilt Stop also protects evergreens from salt damage which can occur when you have a hedge near a road where salt is spread during the winter. Apply according to the label directions.

Until next time – Happy Gardening and try to stay warm!

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Boxwood bronzing in winter

Orange is an interesting color for a boxwood!

Orange or bronze colored boxwood are common in winter but if you aren’t prepared for this color transition, it can be quite alarming to suddenly notice that your boxwood aren’t green any longer!

Several years ago, I wrote a post about this seasonal color change and it always receives a lot of views at this time of the year. The boxwood hedge at the nursery entrance is again sporting its orange and green winter coat. It is so interesting how the Korean boxwood turns orange but the other species of boxwood right beside it remains green throughout the winter.

Here’s the post from February 2012 …

We recently received an interesting question on our discussion board:

I’m curious to know what has caused the leaves on some of my boxwoods to turn orange during the past two months.

Here’s a snippet of the answer I wrote out to him:

“If exposed to full sun and frequent frost and wind, the foliage of some boxwood may become orange or bronze in the winter …”

Such a contrast between boxwood species

Such a dramatic contrast between
two different boxwood species.

This is really quite common especially in certain boxwood varieties such as the small-leaved Korean Boxwood (Buxus microphylla var. koreana).

In fact, the other morning when I was taking pictures in the Viette gardens, I noticed that the Korean boxwood in front of an outbuilding had a very definite orange/bronze tint while the boxwood right beside it, a different species but growing under the same conditions, was still a nice healthy green color. The contrast was striking and a neat display of the seasonal variation that can exist between two different species.

On the protected leeward side, the foliage remains green except towards the top where it is more exposed.

On the protected side, the foliage
remains green except towards the top
where it is more exposed.

Even more interesting is the fact that only one side of the Korean boxwood is showing the bronzing of the leaves; namely the side that faces west and is exposed to the prevailing winds and the sun. The side that faces the building (which is about 8 feet from the hedge) is still green except for some bronzing near the top where branch tips are more exposed. This provides pretty good evidence that the bronzing occurring here on this particular variety is due to the environmental effects of sun and wind. The building is definitely providing the boxwood with protection from the elements.

There are certain things you can do to help protect boxwood and other evergreens from sunburn and winter winds that might cause discoloration of the foliage.

The windward side has become bronzed from wind and sun exposure.

The windward side has become bronzed
from wind and sun exposure.

Most important is to keep them watered during the winter especially when the ground is not frozen. Gardeners often forget that evergreens continue to function physiologically (albeit at a reduced rate) throughout the winter. Cold winter winds can suck moisture from the leaves and if this water is not replaced through uptake by the roots, winter injury can occur. This is why it is important to water your evergreens deeply in the late fall before the ground freezes. During dry winter weather when the ground is not frozen, be sure to check your evergreen trees and shrubs and water deeply if necessary. This is especially important during a mild winter like we’ve been experiencing so far this year. The addition of a layer of mulch will help retain the soil moisture.

Boxwood bronzing

The small-leaved Korean boxwood
typically turns bronze in winter.

Feed your boxwood in the spring and again in the fall with a slow release organic fertilizer like Espoma Holly-tone or Plant-tone to keep them healthy and vigorous.

Spraying evergreens with an anti-desiccant like Bonide Wilt Stop will also help to protect them from winter injury by forming a soft, clear flexible film over the leaves. In colder areas, the more tender broadleaf evergreens like Camellias and some varieties of boxwood and hollies should be sprayed with Wilt Stop and then carefully wrapped in burlap for additional protection from sun and wind.

.

The answer, continued:

“The good news is, though many consider it unattractive, this bronzing will not kill the boxwood and they should green up again once temperatures warm up in the spring.”

Certain branches became more orange

A few branches became a brighter 
orange with no green remaining.

Personally, I think this winter “off-color” adds some interest to the boxwood – sort of like “fall color” in the winter! And keep in mind that for some boxwood like the Korean boxwood, this color change is normal during the winter months.

It is important to note that the overall bronzing of the foliage that I am talking about here is a seasonal discoloration, not winter kill. Winter kill is permanent and must be pruned out in the spring – but that’s another story …

Until next time – Happy Gardening!

Oh and Happy Groundhog Day!

 

Korean boxwood in early April has lost most of the bronze coloration

By early April the Korean boxwood had
lost most of the bronze coloration

A postscript to this post –

That same year (2012) on April 2nd, I took another photo of the same Korean boxwood. The foliage had almost completely transitioned back to its rich green color.

An amazing transformation!

Until next time –

      Happy Gardening!

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