Category Archives: Trees

Damage from PA’s Seemingly Endless Winter!

I realize it’s been a while since I posted something on this blog. I have a bunch of ideas that are ruminating at this time but I think the thing that’s kept me away from the keyboard is this endless winter! While I’ve started a few seeds, I still can’t get into spring mode – the piles of snow and the cold weather are getting to me.

This week I was finally able to wander through the yard and see what kind of damage this winter has brought to the yard and garden.

Weeping Willow Damage

Weeping Willow Damage

The first thing I noticed was obvious from the day it happened but when I got close, I could see how bad the damage is. We had a bad ice storm a month ago. Trees and power lines were knocked down and a lot of people were without power for days. Fortunately I didn’t lose power and most of the trees and bushes weathered the storm. But one tree took a beating. The weeping willow in the back part of the yard is a mess. While there aren’t a lot of branches on the ground, many of the branches of the tree are split and cracked. Once the weather warms, I’m going to be spending some time on a ladder with a saw to clean it up.

It didn’t surprise me that the willow was damaged by the freezing rain. Willows grow fast and their wood is very soft. The weight of the ice was just too much for many of the branches. The good news is that the tree’s still fine even if it has lost a quarter to a third of its branches.

Pear Tree with Rabbit Damage

Pear Tree with Rabbit Damage

What might not be as fine are the two asian pear trees. They’ve been growing for a number of years and were doing well. I put some chicken wire around the base of the trucks to protect them from rabbits chewing on the bark. The wire worked until this year. This winter the snow was so deep and stayed for so long that it allowed the rabbits to gnaw on the pears’ trunks.

The only part of a tree trunk that’s alive is the outer ring just beneath the bark. This area contains the cambium layer which allows the truck to expand. Also the tree’s phloem is located under the bark and it transports nutrients created in the leaves down to the roots. If these tissues are too damaged, the tree won’t be able to grow, the roots will starve and the tree will die. I don’t know if the rabbit damage is lethal or not… only time will tell. If the pears do survive, I’ll be wrapping the trunks in chicken wire next fall!

Burning Bushes with Rabbit Damage

Burning Bushes with Rabbit Damage

The other plant that the rabbits took a liking to this winter was the burning bushes (Euonymus alatus). The branches of these bushes are all chewed up and uneven. But this damage doesn’t have me too concerned. Burning bushes are basically weeds (some states such as Massachusetts and New Hampshire have outlawed them because of their invasive tendencies). In the spring I’ll trim them back and they’ll be fine. Also, given all of the rabbit dropping that surround them, they’ll have a nice shot of fertilizer to aid in their recovery!

It’s been a winter here in PA and there’s more snow on the way today. There’s a lot of damage in the yard to clean up when the weather warms. But after this winter, it’ll be enjoyable to just be outside, even if it is to cut bushes and trim storm-damaged trees.

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What Is That? Oh, It’s a Treegator!

I noticed something strange in the yard of a church that I drive by regularly. They recently had some trees planted along the road and surrounding the base of each of the trees was a green bag. I had no idea what they were or what was their purpose. I thought it might be to protect the trees from being girdled by rodents, but that’s a problem in the winter, not in the spring. I was stumped (no pun intended!) as to what those green bags were.

A quick Google search answered my question. I typed “What are the green bags around trees” and my answer popped right up – Treegators.

Treegators

Treegators

A Treegator is a tree “irrigator.” It’s a bag that goes around the base of newly planted trees and is zipped closed. Once it’s around the trunk of the tree it can be filled with 20 gallons of water that’s slowly released through two holes in the bottom of the bag. According to the Treegator web site, it can take from 5-9 hours for the water to leave the bag. This slow watering ensures that the water doesn’t run off or evaporate; instead it soaks in deeply around the base of the tree. The bag needs to be filled once a week in order to keep the soil moist and help the tree get established.

My first thought was who needs a Treegator? Can’t you just make sure that you soak the ground thoroughly once a week? People have been planting trees without a Treegator for millenia – is it that important?

But the more I thought about it, the more it made sense, especially for landscapers, municipalities and for home owners with a less than green thumb.

One of the main problems when it comes to watering is that most people don’t water enough. They go out with a sprinkler, wet the top part of the soil and say they’ve watered. But this little bit of watering can cause more harm than good. If only the top of the soil is moist, most of a plant’s roots will stay in that top layer. This lead to the plant being especially susceptible to drought. Watering deeply helps the roots to grow down where they’re less affected by fluctuations in the soil moisture.

This is an issue with all plants but it’s especially the case with newly planted trees. How many homeowners will take the time to slowly water a transplanted tree? Not many! How many landscapers or townships will come out every week to water a new tree? Again, not many! What the Treegator does is provide a way to water a newly planted tree deeply and easily. Most people would be willing to go out once a week and spend a few minutes filling a bag with water. Even municipalities or landscapers could find the time/manpower to do that.

It’s such a simple idea but it solves the problem of watering newly planted trees. I don’t think I’ll ever buy a Treegator – I enjoy going out to a new tree and watering with a hose set at a slow dribble. But I know I’m the exception; most people wouldn’t want to spent the time. The Treegator solves that problem and make sure that the tree is watered deeply. What a simple but great idea.

And now I know what those green bags are – they’re Treegators!

Eastern Redbud aka The Judas Tree

The eastern redbud (Cercis canadensis) is in full bloom right now. You can see them in wooded areas, adding a pop of color to the green and brown landscape. They’re also in many neighborhood yards. This small tree seems to be a favorite for homeowners given its size and the display it puts on in the spring.

Eastern Redbud

Eastern Redbud

In doing some research on this tree, I was surprised to learn that it’s sometimes called the Judas tree. The name “Judas tree” is specifically paired with another Cercis species, Cercis siliquastrum, a similar looking tree that’s native to Southern Europe and Western Asia. As is often the case with common names, they can be applied freely to plants of the same genus or those with similar characteristics.

There are lots of stories about how the name Judas tree became associated with the redbud. Some state that Judas hung himself on this tree. Others point to the dangling seed pods that hang from the tree, saying that they’re reminiscent of Judas’ hanging body. Longer tales say that the redbud was once a larger tree, but after Judas hung himself on it, the tree asked God to prevent this from happening again so God made the redbud smaller with weak branches that couldn’t support the weight of a hanging body. Ah, the tales of medieval Europe!

Whether God granted the tree its wish or it’s just evolution’s path for the redbud, one thing is true – you couldn’t hang yourself from this tree! The branches are pretty low to the ground and they aren’t very sturdy. A few years ago we had a surprise snow in late October and a lot of redbuds lost branches. The weight of the snow on the leafy branches was more than they could support.

In most landscapes the redbud is grown for its flowers. The small flowers emerge in clusters in early spring and look just like pea or bean flowers. The redbud is a member of the Fabaceae family, the legume family, which includes peas and beans so the similarity isn’t surprising. The seed pods that are produced from these flowers also look like pea pods.

I’m always amazed by how the flowers of the redbud emerge from the trunk and large branches of the tree. In most flowering tree, the flowers develop at the ends of branches or from spurs along the branches. While very different, the redbud make me think of the cocoa tree where the cocoa pods grow from the trunk and large branches.

Growing a redbud is pretty easy – the tree doesn’t have a lot of disease or pest problems. They don’t like to be transplanted (like their relatives the pea and bean!) so it’s recommended that small balled and burlapped or container grown trees be used for planting. The trees don’t need a lot of fertility, in part because they can produce their own nitrogen from the air like other legumes. Once redbuds are established, they’re very drought tolerant. The only downside to the redbud is that it’s not a long-lived tree – they seldom live past 40 years. But for most homeowners, 40 years is long enough!

I doubt I’ll ever call a redbud the Judas tree but if I ever hear that name, I’ll know what people are talking about. I’ve included some pictures of the redbud flowers to this post. After all, they’re the reason for growing this native tree! Up close, they’re fascinating.

redbud4

redbud2

redbud3

More Spring Blooms

I have to say that this is turning out to be a great spring for flowers. The temperatures are staying cool so the flowers are opening slowly and lasting a long time.

In this set of photos there are some tulips which have just started to bloom. I wish I knew the name of the two-tone one – the colors are the most amazing I’ve ever seen in a tulip and the close up looks like something you’d see in a bulb catalog! Also there are two different varieties of asian pear in the pictures. One of them has double blooms and almost looks like a rose.

It’s so nice to see nature starting to burst out in its spring finery! (Click on any of the photos to enlarge them)

 

Tulip

Tulip

 

Tulip

Tulip

 

 

Muscari or Grape Hyacinth
Muscari or Grape Hyacinth

 

Eastern Redbud

Eastern Redbud

 

Asian Pear

Asian Pear

 

Asian Pear

Asian Pear

 

Asian Pear
Asian Pear

 

The Weeping Cherry Tree – A Graft Chimera

Weeping Cherry

Weeping Cherry

As I’ve been driving around the area, I’ve noticed that a lot of people have weeping cherry trees in their landscape. These trees can be beautiful with their large, arching branches covered with light pink blooms this time of year.

But for every 5 or 6 large stately trees that I see, there’s one that looks terrible. Sometimes it’s misshapen. Other times only half of the tree’s canopy is healthy. And then there are the trees that have some arching branches but also have large upright branches that don’t have many flowers.

After a little searching online, I learned that most weeping cherries are grafted trees. Grafting is process where tissue of one kind of plant is inserted into tissue of another plant and the two grow together, developing a shared vascular system. In botanical terms, these grafted plants are call chimeras or graft chimeras. The Chimera is a mythical animal that combines a lion, goat and serpent  A graft chimera is a plant that combines two or more different plants into one single plant.

One of the most common kinds of grafted plants are tea roses. The wanted rose variety (called the scion) is inserted into the base of a rose variety with a better root system (called the rootstock). The result is a chimera, a grafted plant with a strong root system and beautiful flowers.

I’ve also been noticing that some places are offering grafted tomatoes. In this case, an heirloom is the scion and the rootstock is a stronger, better rooting tomato variety. It’s said that a grafted heirloom tomato will produce twice the fruit of the same variety grown from seed with its own root system – I’m a little skeptical but maybe it’s true!

All of the weeping cherries that I’ve seen are grafted varieties. You can tell because all of the branches develop from one spot about 5′ above the ground. To make this tree, one variety of cherry (a non-weeping variety) is used for the rootstock. The top is cut off, leaving a single trunk about 5′ tall. Then a ring of twigs of the weeping variety (scion) are grafted into the top of the trunk. If all goes well, the vascular systems of the rootstock and scion merge and you have a grafted weeping cherry tree.

Weeping Cherry with Upright Branch from Root Stock

Weeping Cherry with Upright Branch from Rootstock

If some of the weeping cherry scions die, the tree can look deformed or lopsided. When the rootstock sends out a shoot and it’s not removed, you can get a tree that has weeping branches and upright branches.

I saw this latter problem in a tree growing at the local school’s administrative building. The tree has nice weeping branches but there is also a large, upright branch growing in the middle of them. A closer look showed that below the graft site, a branch had grown out of the trunk. Since this branch has the genes of the rootstock and not the scion, it’s upright and doesn’t flower very much.

This unsightly problem could have easily been avoided if the shoot below the graft site had been removed when it was small. But this branch has been growing for a number of years and will take some major sawing to remove it.

IMG_0775With any grafted plant, you always have to remember that it’s a chimera – two or more plants in one. The graft site has to remain above the soil line – not an issue with a weeping cherry but important for roses. (If the rose is planted too deeply, the scion will develop roots and the benefit of a vigorous rootstock will be negated.) Also any shoots growing from the rootstock have to be removed or the chimera will start to show the characteristics of both the rootstock and the scion.

I really like weeping cherry trees. There’s an elegance about them that’s appealing. But if I ever grow one, I’ll be sure to remove any shoots that develop below the graft site. If I’m growing a weeping cherry, I want it to weep, not grow upright!

Fall Colors: Part III – Leaf Fall

Trees Post Sandy

Two weeks ago Hurricane Sandy passed directly over this part of PA. While we didn’t suffer the devastation of the Jersey shore, we did have rain and wind. But even with all of the wind, the leaves stayed on a majority of the trees. That got me thinking about how leaves fall from a tree. I was reminded of one of the few things I remember from plant anatomy class and it all has to do with some special cells that connect the leaf to the twig.

As a tree gets ready for winter, it has to somehow deal with its leaves. If the leaves were to stay on the tree, there would be a lot of damage in the winter due to the weight of snow building up on the branches and leaves. Just think of the damage that occurs when we have an early snowfall before the leaves are gone. Somehow the tree needs to lose its leaves before the winter weather.

But the tree also has to accomplish this leaf loss in such a way that there isn’t a lot of exposed tissue. If leaves were just pulled off of a tree, the places were the leaves were connected to the twig would be an open wound. This would be an avenue that would allow bacteria and fungi to enter the tree. So the tree needs to not only lose its leaves but also do it in a way that protects it from pathogens.

Deciduous trees and bushes have evolved a way to lose their leaves in the fall (abscission) while doing so without creating open wounds. It all has to do with the abscission zone.

In the area where the petiole of the leaf (the small “stem” of the leaf) joins the twig, there’s an abscission zone made up of two kinds of tissue – the abscission layer and the protective layer. The protective layer is closest to the twig; the abscission layer is between the protective layer and the petiole. Both of these layers are only a few cells thick. During the growing season this layer of cells is healthy and keeps the leaves attached to the tree. But when the days become shorter, things begin to change in this zone.

The protective layer begins a process called suberization in which suberin, a waxy chemical found in cork, builds up in the cells. This provides an area of tissue that’s impervious to the outside elements. The suberized protective layer prevents leaf fall from leaving open wounds on the twigs.

While the protective layer is becoming filled with corky tissue, the abscission layer also transforms. Chemical changes in the tree cause this layer of cells to break down. When the cell walls have broken down sufficiently, the leaf will fall and the protective layer will show on the twig as a leaf scar.

It could be said that the leaves on a tree don’t fall so much as they are released by the tree. The tree breaks down the abscission layer and when it does, the leaves are sloughed off. Each kind of tree releases its leaves on its own schedule. In my yard the asian pear and redbud lose their leaves in early October while the maple and willow are just beginning to lose their leaves in mid November. When the abscission layer breaks down is species dependent but it eventually breaks down in all deciduous trees.

Sandy blew through the neighborhood but she couldn’t remove the leaves from the trees because they weren’t ready to be shed. But now the leaves are starting to fall in earnest. The protective layers have suberized and the abscission layers have broken down. The trees have done their part to prepare for winter. Now it’s time for me to do my part – rake the leaves!

Fall Colors: Part II – Red, Crimson and Purple

There are years when the colors of the autumn leaves are stunning and there are other years when the display is a little muted. A lot of this difference has to do with the red, crimson and purple colors of fall.

While the yellow colors (carotenoids) of fall are generally consistent from year to year, the same isn’t true for the various shades of red. The pigments that cause these colors in the leaves are anthocyanins, the same pigments that give color to cranberries, apples, cherries and grapes. While carotenoids are present in the cells of the leaves all year-long, anthocyanins usually are not. Also not all trees produce anthocyanins – for example, you won’t see red leaves on an aspen. Trees that do produce this pigment, like maple trees, do so in the fall.

In order to have a bright red display of leaves, the conditions need to be just right. The best reds are produced when the days are warm and sunny and the nights are cool but not freezing. During a warm, sunny day in the fall, the remaining chlorophyll in the leaves is able to photosynthesis and produce a lot of sugar. This it the same process that goes on throughout the growing season.

But when the days become shorter, the vascular tissue of the leaves begin to shut down. The sugars that easily moved from the leaves to the tree during the summer now become trapped in the leaves. Cool nights mean that there’s little breakdown of the sugar. The result is that the leaves become saturated with sugars.

When there’s lots of sugar in the leaves and the days are sunny, the tree leaves convert the sugars into anthocyanins. These pigments are water-soluble and are stored in organelles within the leaves called vacuoles. Vacuoles are membrane enclosed structures used for storage of water and other materials. When the days of fall are sunny and warm and the nights are cool, these vacuoles become filled with anthocyanins. Later in the fall when the chlorophyll of the leaves finally breaks down, the anthocyanins can be seen and the leaves appear red, crimson and/or purple.

Since these pigments are found in the water-filled vacuoles of the leaves, the amount of moisture in the soil can also affect the fall display. If there’s a lot of water in the leaves, the anthocyanins can end up being diluted and the resulting colors will be less intense.

With all of the varying factors of light, temperature and soil moisture, no two autumn displays of color will be the same. Some years the red pigments will be intense; other years they’ll be absent. It all depends on the leaves’ ability to produce anthocyanins and the amount of these pigments that are stored in the leaves.

It’s exciting to know that each year will be different and the combinations of these environmental factors will lead to different shades of red, crimson and purple. Add to this the fairly consistent yellows and each autumn display is unique. Someone should take pictures of the fall colors from the same location on the same day for a number of years. It would be fascinating to see the differences in the display from year to year. While they’d all be different, they’d also all be beautiful in their own way.