Monthly Archives: April 2013

Roundup – What’s in that Bottle?

I’ve been a bit hesitant posting about Roundup, the non-selective herbicide. In some circles the word “Roundup” has become a shibboleth dividing the world into those who are environmentally conscious, opposed to big business and against genetically modified crops and those who aren’t. Personally, I’m somewhere in the middle on this whole debate. But in this post I just want to talk about what Roundup is, how it works and what’s in the bottles of Roundup lining the shelves of garden centers.

What got me thinking about Roundup was some of the commercials that I’d seen on TV for this product. One said that one kind of Roundup would kill weeds within a few hours. There’s also a commercial for a Roundup formulation that will continue to prevent weeds for up to three months.

Back when I was in college, Roundup was a fairly new and highly touted product. In a weed science class (yes, there are weed science classes!) we learned about how it worked and what it does. What I’d learned in that class was that Roundup doesn’t kill weeds instantly and it offers no extended control. So what’s up with those commercials that I’d seen?

The active ingredient in Roundup (at least it used to be) is glyphosate. This chemical is called a non-selective or broad spectrum herbicide because it doesn’t distinguish between different kinds of plants. Basically, if it’s green, glyphosate will kill it.

The way glyphosate works is interesting. When sprayed on a plant, the chemical is absorbed and tends to accumulate in the meristem of the plant. Meristem is a kind of tissue in plants that’s undifferentiated and can produce all kinds of different cells and tissue. You could call it the stem cells of a plant. The growing tip of a plant has apical meristem which produces leaves, stems and allows the plant to grow. Root meristem is located at the ends of roots and produces the various tissues that make up the root. Meristem is some of the most active tissue, constantly dividing and differentiating. While accumulating in the meristem, glyphosate also finds its way to the chloroplasts of the cells where photosynthesis happens.

When glyphosate is present in a plant, it attaches to an enzyme called 5-enolpyruvylshikimate-3-phospate or EPSP synthase. This enzyme is involved in a key step in the production of the amino acids phenylalanine, tyrosine and tryptophane. When glyphosate is attached to the EPSP synthase, the enzyme stops working and the plant can’t produce these three amino acids. Without them, the plant can’t make proteins containing these amino acids, the building of cell wall is disrupted, hormone production is interrupted and energy transport is stymied. While this biochemical disruption affects the whole plant, it’s especially harmful in the chloroplasts and the actively growing meristem.  The plant begins to starve and dies within a week or two.

The other thing about glyphosate is that it doesn’t remain effective outside of the plant for very long. The chemical binds to the soil and is broken down by microorganisms. You can notice this if you mix up some Roundup in a sprayer that isn’t clean. After a few days, it becomes less effective because the glyphosate binds to the dirt in the sprayer and can’t be absorbed by the plant.

I know this is a lot of technical information, but all of this was in my mind while seeing those Roundup commercials. Since glyphosate interrupts amino acid production, it can’t kill a weed in a few hours – it takes at least a week. And since it binds to soil, it’s not a long acting herbicide – it only affects the weeds that are sprayed with it.

Roundup-Weed-_-Grass-Killer-Super-Concentrate-stdSo this sent me on a search to the Scotts web site and I have to say that I was amazed. Back in the day, Roundup was glyphosate, period. But that’s not the case any longer. The fast acting Roundup has glyphosate but also diquat, a fast acting herbicide. Extended control Roundup also has glyphosate but added to it is Imazapic, an herbicide that prevent the germination of seeds. There’s also a Roundup for poison ivy that has glyphosate and Triclopyr, an herbicide for woody plants. If you’re looking for just glyphosate, you have to do some hunting; according to the site, only one Roundup product for use by homeowners (Roundup Super Concentrate) is just glyphosate.

Why are there all of these different formulations? I have my guesses! The only one that makes sense to me is the poison ivy product – woody weeds are hard to kill and the addition of a woody weed herbicide would likely make the product more effective. The others seem to me to be little more than attempts to appeal to suburban gardeners. People want weeds to die instantly; glyphosate takes a little time. So by adding diquat to the mix, people get faster, visible results. The extended control appeals to people who want to spray once and be done.

The other thing that has probably led to all of these formulations is that the patent on glyphosate expired in the year 2000. Now any company can use glyphosate; these various formulations help to keep Roundup competitive.

As I’ve said before, I’m OK with conscious and limited use of chemicals in the yard. But I like to know what I’m using and like to use the least possible. I find glyphosate works well for killing weeds in places were they can’t easily be controlled with cultivation. But I don’t want to use a mixture of chemicals if one will do the job. I don’t need instant results when I spray weeds. I also prefer to spray as needed and not use an extended control product that stays active in the soil for months.

Before I learned all of this, I thought Roundup was glyphosate. Now I know that’s not the case. I have some Roundup in the garage that has glyphosate and diquat – I’ll use what I have but from this point on, I’ll be reading the labels before I buy any more Roundup. I want to know what’s in the bottle before I use it.

 

Parrot Tulips and Tulips in a Pot

I know I’ve posted a lot of photos lately but what can I say – there’s a lot of things to take pictures of right now!

On March 5th I posted “Tulips in a Pot” where I wrote about a trick I learned from P. Allen Smith to provide tulip bulbs with a cool period and then plant them directly into pots. Here’s a photo of the tulips in a pot this year.

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Also the parrot tulips have started to bloom. I just love these flowers. Instead of the elegance of a Darwin tulip, parrot tulips have a wildness about them that’s appealing to me. The photos show how bright these flowers are. This is their real color – no Photoshop adjustments on these photos! I also like to get in close with a wide aperture and focus on different parts of the flowers, throwing the other areas out of focus. Parrot tulips are worth growing for the crazy burst of color that they provide in the garden.

Even the Pistil of a Parrot Tulip is Curved and Twisted

Even the Stigma of a Parrot Tulip is Curved and Twisted!

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My Purple Tomato Seedlings – Feed Me!

It’s time for a confession – I can sometimes be obsessed with words and their usage. This is especially the case when it comes to plants. If I hear someone say “the plant needs a drink,” I can feel my back tightening up! Plants can’t drink; they absorb water through osmosis and hydrate. Like I said, I can get a little obsessive about word usages.

Because of this tendency, I also don’t like phrases like “plant food” and “feeding your plants.” I hear the word “food” and I think of eating – plants don’t eat. Plants take up needed nutrients and minerals and through the process of photosynthesis make their own “food,” or what I’d prefer to call photosynthate!

But one of the dictionary definitions of “feed” does make sense when it comes to plants – “to furnish something essential to the development, sustenance, maintenance, or operation of.” I guess you can “feed” a plant.

I write all of this because of something that recently happened with my tray of tomato seedlings. I noticed that one side of the tray was green and growing well while the other side had plants that were smaller with a purple tint to the leaves and stems. It looked like there were two different varieties of tomato in the tray but that wasn’t the case – they were all the same variety.

Tomato Seedlings - note the smaller, purple plants on the left.

Tomato Seedlings – note the smaller, purple plants on the left.

Phosphorus deficiency can often lead to plants that have a purple color in the stems and leaves. But why would half of the tray be OK while the other half was suffering from a deficiency of this nutrient?

I thought back on what I had done to this tray of tomatoes and it all started to become clear. The potting mix that I like to use is a local gardening center’s own formula. I’ve found that plants grow well in it but it doesn’t have any added fertilizer. I had started the seeds of the tomatoes in this mix and I had used this mix when I transplanted the seedlings into the tray. A few weeks ago I had made up some worm casting tea and poured some of it on the tomatoes. But I hadn’t poured it on the whole tray; I had added it to one side of the tray, assuming that it would infiltrate into all of the soil.

If I had added a lot of the worm casting tea to the soil, drenching the tray of seedlings, I wouldn’t have had this problem. But the mix wasn’t very wet when I added the tea so the nutrients in the liquid stayed localized. One side of the tray had plants that were growing well – you could say they were “well fed.” The other side of the tray of seedlings was starting to show signs of nutrient deficiency. The purple leaves and somewhat stunted growth was a clear signal that “something essential to their development” was missing – they weren’t being “fed.” If those tomatoes were like Audrey II from Little Shop of Horrors, they would have been crying out, “Feed me, Marc!”

So that’s what I did. I have some African Violet “Food” that has micro nutrients and a 7-7-7 N-P-K (nitrogen, phosphorus and potassium) ratio so I knew it would provide what the tomatoes needed. I added this liquid fertilizer to the entire tray of seedlings and now, only a few days later, I can see a difference. The youngest leaves on the phosphorus deficient plants are more green and less purple.

Tomato Seedlings after Adding Phosphorus

Tomato Seedlings after Adding Phosphorus

Next time I’m starting plants in this potting mix, I’m going to be more conscious about fertilizing the seedlings. I know the dangers of over-fertilizing so I tend to go to the other extreme and under-fertilize. It’s time to seek a middle ground regarding fertilizer.

The amazing thing in all of this is that the plants let me know what they needed. The purple leaves were a message delivered loudly and clearly. The message I took from those leaves was that something essential was missing from the seedlings’ soil. But maybe I can lighten up a little bit and admit what the message really was – “Feed me!”

(But if the soil ever gets dry and the plants wilt, I’ll won’t say they “need a drink” – I have my limits!)

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!

Daffodil and Narcissus Photos

While I usually take pictures of plants and flowers in the natural environment, sometimes it’s fun to bring the flowers inside, set up the tripod and take some close up photos. Inside I don’t have to worry about wind or other factors; I can just focus on the shape and color of the flowers(s).

Here are some pictures of various daffodils and narcissi. As you can see, I like the more unusual varieties of these spring bulbs. You can click on any picture to enlarge it.

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Spring Flowers

I spent this weekend taking a few pictures of the spring flowers. While most of the tulips and later bulbs still haven’t bloomed, the daffodils, hyacinth and peach tree are putting on quite a show. (Click any picture to enlarge)

 

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