One of the great things about doing a multi-author science blog is that there will be topics about which colleagues will disagree. One of those topics revolves around the best way to prepare woody rooted plants (trees and shrubs) before planting them. This is an area in arboricultural science that is evolving. A search through our blog archives will find many of these posts and for convenience’s sake I’ve linked one from each of us here.
Rather than belabor the points that Jeff, Bert and I have already made in our posts, I think I can sum up our major difference here: I like to bare-root trees and shrubs completely before planting (so I can correctively prune all flawed roots) while Bert and Jeff prefer a less invasive approach. What we do agree upon, however, is the deplorable condition of the roots of many trees and shrubs that end up in the nursery. Because I do practice bare-rooting trees, I thought I’d use today’s post as a rogue’s gallery of trees that should never have made it to the retail nursery. (All of these trees were ones that I bare-rooted and root-pruned myself before planting – and all are thriving.)
Ginkgo “knee” rootInterlocking redbud rootsJunky Japanese mapleThe duct tape around the trunk is where the burlap bag began. While the roots are in pretty good shape, root-washing revealed the root crown of this tree (which the “at grade” part of the tree) 10″ below the top of the bag
I admit it. I can’t keep up … I’m not as industrious as most of my gardening friends are when it comes to the effort necessary to manage my 6 acre landscape.
It can get overwhelming, especially when there are previous beds that came with the property that had been neglected for 10 years or more by the elderly lady who owned the property before us, and where perennial weeds are well established.
I make a valiant effort in the Spring, with all the enthusiasm of the new season to clean them up … dig the perennial weeds … plant something new (usually a division, or a naturally layered specimen, from elsewhere, or one shared from friends), but by mid-July or so, I have to redirect my efforts to the places that I’ve created … the shade garden … the rock (mostly sedum) garden … mulching the new trees and shrubs, and of course my tomatoes, so these previous places don’t get the attention they deserve.
But then again, some surprisingly beautiful, and beneficial results can happen in spite of (because of?) the neglect …
This is a “pre-me” bed of mostly Japanese Anemone stretching between two arbors, with Trumpet Vine (Campsis radicans) (pre-existing), and Climbing Hydrangeas (Hydrangea anomala) (me added), anchoring each end.
The Goldenrod (Solidago) and White Snakeroot (Ageratina altissimaI think) now dominate, along with Sweet Autumn Clematis (C. terniflora), a non-native introduction that appears on watch lists as an invasive species in our area.
Yet look at the insect life. Scads of hoverflies (some species of Syrphid), who in addition to their role as pollinators as adults, are voracious consumers of aphids in their larval stage.
I get versions of this question often. You have something in the garden, but this year it looks a bit different than it did before. There are a bunch of different things that could have happened to cause this change, and I’ll attempt here to make a complete list of them.
Rootstock
Trees and shrubs, including things like tree peonies and roses, are often grafted, so the part with the pretty flowers or delicious fruit is stuck onto the roots of a different variety, often not as pretty/useful/tasty but more vigorous and/or easier to propagate. Sometimes shoots come up from that rootstock and take over the plant. The best sign will be to see if the shoots that look different are coming up from the very base of the plant. Cut all the shoots with the off-type flowers or fruits as completely as possible to allow the desirable parts of the plant to continue on.
Reversion
This is most common with variegated plants that are chimeras, though there are a few chimeral varieties which have multicolored flowers rather than multicolored leaves. I wrote about what a chimera is here, but the short story is: Many variegated plants are made up of two different cell types living together. If one cell type starts taking over, you loose the bi-colored effect of the variegation. As soon as you notice them, cut out the reverted shoots to keep them from out growing the multicolored parts.
A variegated sport on a lilac
Sports
Sports are chance mutations, and sometimes a flower will just up and change color. Usually, a sport will only change one aspect of a plant, most often color, while size and shape and everything else stays the same. New variegated varieties almost always come into being as sports. Sports will almost always be isolated to just once branch or section of the plant while the rest of the plant maintains the original color. If you like the sport, you might want to try taking cuttings. If it is an attractive sport of a popular plant, it might even be valuable.
Seedlings
Sometimes it isn’t that the original plant changed, but rather that it had some babies, and the babies look different. Confirmed self-sowers like phlox and aquilegia are notorious for this. You get a nice variety, but in a couple years, it has died out and replaced by a few seedlings which usually aren’t as nice. To prevent this, dead head after flowers fade to prevent seeds from developing.
Soil
Hydrangeas famously will change flower color depending on the pH of the soil in which they are grown. However, this is rather an anomaly, and soil conditions have no impact on the look of flowers for the vast majority of plants.
Climate
Some flowers will change their look, sometimes radically, depending on climatic conditions, often getting darker or lighter depending on temperature and the amount of sunshine. So if a plant looks different in a year when it has been unusually hot or cold or cloudy or sunny, it will probably go back to the normal coloration once your weather returns to normal.
Nursery conditions
Often plants you get at the nursery will look quite different once they’ve spent some time in your garden. Many plants from the nursery will have been treated with chemicals called plant growth regulators which are used to keep the plants short and compact. As those compounds wear off, the plants will grow taller and looser. Also, commercial greenhouses are usually warmer than your garden and often exclude UV light which can chance the coloration of a lot of flowers.
Contamination
If your neighbor gave you a clump of their favorite old bearded iris, but after a couple years the iris they gave you is replaced by a different color or a different plant altogether, they likely accidentally included a bit a different, more vigorous plant along with the one they gave you. Your best option here is to lift up the whole clump, wash all the soil off the roots so you can see exactly where one plant ends and the other starts, and just replant the ones that are true to type.
A whiff of glyphosate caused this iris flower to bleach out.
Herbicide drift
If you are spraying something like glyphosate (active ingredient in roundup) sometimes a bit of it can drift onto plants, not enough to kill them, but enough to cause them to be deformed or discolored. Glyphosate drift in particular will often cause flowers to be bleached out, white or nearly white. In this case, just be more careful next year, and everything should return to normal.
Forgetfulness
Okay, let’s just admit it. We don’t always remember that we moved something or what we bought or exactly what a new plant looked like last year. Sometimes there is no great scientific mystery beyond the fact that we’re all busy and don’t keep as good records as we know we should.
For all five of you that might have paid attention to my posts on the genus Puya (which does in fact rhyme with booyah…thank you my west-coastie friends):
Here’s the update that you’ve been waiting for!
Puya is a horrifically spiny, painful, and hateful genus in the Bromeliad family. Native to the Andes, the fish-hook-like spines snare passing mammals; the rotting flesh provides nutrients to the exceptionally lean soil of the arid steppes on which it sort of grows/becomes grumpier.
Puya flowers once an eon, in a spectacular [but ill-earned] display that turned me to mush, based on a photo in an Annie’s Annuals catalog (see my “eternal gardening optimist” post). Autumn of 2012, I ordered and received one healthy Puya berteroniana in a 4” pot. Heckling commenced. Overwinters in a 40 F greenhouse, where it was watered once or twice. Summers have been spent on our deck. Osmocote has hopefully provided required nutrients. Expected to kill her within months, as it is SO VERY not native to the verdant and humid Blue Ridge mountains of Southwest Virginia.
Happy and amazed to say Pootie [what was I going to name her? Bert??] is in her 3rd year – continuing to grow, and, AND, captured her very first mammal!
Okay… so it’s a fluffy stuffed possum, and the dogs dropped it from the deck above. But snagged! You know Pootie got a thrill…
In many parts of the U.S., particularly the northern U.S., we are blessed each year by nature’s display of bright color dotted through the landscape. Fall color of leaves at the end of the growing season provides a remarkable encore in the landscape. There are many trees and shrubs with great autumn leaf color and I will address some of them in my next week’s post, but this week, I will talk about what actually happens inside the plant during autumn.
Plant Pigments
As the days get shorter and temperatures start to cool, particularly at night, the season changes from green leaves into a kaleidoscope of yellow, orange, red, purple and bronze shades. There are a variety of factors that interact and play a role in determining how colorful the display will be. Plant leaves contain several pigments that determine the color that will appear and variations arise when different concentrations of pigments are combined in the leaf.
Eyestopper™ Amur corktree (Phellodendron amurense ‘Longenecker’), a male cultivar with bright yellow fall color
Chlorophyll is the green pigment in leaves. This critically important pigment captures the energy from the sun and uses it to change water and carbon dioxide (CO2) into oxygen and sugars (carbohydrates), i.e. the plant’s energy source for growth and development. In autumn, chlorophyll breaks down faster than it is produced, revealing the other plant pigments and their colors.
A cutleaf weeping Japanese maple (Acer palmatum) bright orange fall color
Carotenoids are responsible for the yellow, orange and a few red pigment colors. This pigment is always present in the leaves during the growing season, but the colors become more evident as the chlorophyll breaks down in the leaf. In addition to providing us with a beautiful display, carotenoids protect leaves from harmful byproducts of photosynthesis. Since carotenoids are always present in leaves, yellow, gold and orange colors are least affected by the weather.
Anthocyanins are responsible for most of the red, pink, and purple colors we long for in autumn. Sugars in leaves accumulate as active growth slows down in autumn permitting the production of anthocyanins. These colorful pigments act as an internal sunscreen to protect the photosynthetic system allowing plants to recover nutrients from the leaves more easily as the temperatures decline. What about plants that have no anthocyanin pigments? These plants are usually more resistant to damage from bright light so they have no need to produce these protective anthocyanin pigments.
Tannins are not considered an actual plant pigment, but are responsible for some of the tan and brown colors we see in oaks and beeches in the fall.
Why Do Leaves Change Color?
During the summer, most of a plant’s nutrients are located within the leaves. The shortening of day length and cooler temperatures, particularly at night, signal the plant to begin preparing for winter by transporting carbohydrates (sugars) and mineral nutrients from the leaves to stems and roots for storage in the plant to be reused the following spring. A layer of cells at the base of the leaf stalk (petiole), called the abscission zone, gradually closes off the flow of sugars and minerals into and out of the leaf. In a process called senescence, chlorophyll breaks down causing the leaves to change color and eventually fall off the plant.
Variability of Fall Color and the Role of Weather
Many factors play a role in determining when fall color occurs and the intensity of the color. We cannot predict each summer how the autumn leaf color will be in the landscape. For example, peak (best) fall color can shift by as much as two weeks ahead or behind the normal time peak color occurs year to year based on the weather.
Plant Health and Moisture Levels
Plants that are in transplant-shock (newly planted), drought stressed, nutrient deficient or suffer from insects or diseases may have poor fall color or the exact opposite; they may have better fall color due to increased production of red pigments. Good soil moisture levels throughout the growing season followed by a dry fall can improve the intensity of fall color. On the other hand, excessively wet or drought conditions can cause poor color development. Drought conditions can cause leaves to dry, curl and drop before fall color has sufficiently developed, especially on newly planted material. However, moderate drought conditions may actually improve fall color development in some species, though these same plants may suffer during winter and have dieback apparent in spring.
Temperature, Light Levels and Mineral Nutrition
Cool, dry, sunny fall days with cooler night temperatures stimulate anthocyanin production resulting in bright reds and purples. In contrast, very warm autumn weather may reduce the production of these pigments. During unusually warm autumns, plants may accelerate fall color development, shortening the time leaves remain on the tree or shrub. Early, hard frosts may also severely damage leaves, arresting further fall color development before the brightest colors are revealed. Sufficient sunlight is required for leaves to produce the best coloration. Plants growing in dense shade will usually fail to develop the intense red and orange colors we have grown so fond of each autumn. High soil pH and deficiencies of the various essential mineral nutrients, such as nitrogen, phosphorus, magnesium, iron and high levels of the non-essential element sodium can all affect the intensity of color change in leaves. High sodium soil levels, most likely due to excessive road salt (NaCl) application the previous winter, not only stresses plants and prevents proper water uptake, but also can negatively affect autumn leaf color.
Genetics
Of course genetics play a key role in the intensity of fall color development. This is why some seed produced trees in the forest have great fall color, while seedlings from the same tree may have less intense or even no fall color. This is where plant cultivars come into play. A nursery person will select plants demonstrating superior fall color, improved cold hardiness, increased pest resistance, better growth form, etc. These superior plant choices will often have a cultivar name associated with it. For example, seedling grown red maple (Acer rubrum) will display a range of fall color from green, yellow, yellow-orange, orange, orange-red, red and purple. As gardener, we tend to choose what we like, mostly the orange, red to purple colors. If the plant is not already in commerce, the grower will select the best seedlings for fall color and vegetatively propagate and grow those particular seedlings, offering these new selections to other nurseries or garden centers. It is a win-win for both the nursery and the gardener!
An unknown cultivar of red maple (Acer rubrum) with uniform fall color
Though psychology was the subject of this study, you shouldn’t assume the results were unique to that particular field. The are plenty of reports of similar failings and the so-called ‘Decline effect’ in other scientific disciplines.
So why is that? There are a lot of reasons. Research can be poorly designed, based on flawed assumptions, and sometimes an unlucky flukes can create false positives. It is also the sad fact that science is done by humans, and humans are complex things with a lot of motives besides the pure quest of knowledge.
I think the general public often fears that scientists are swayed by money from corporations and/or special interest groups, but my experience in academia is quite different. I’ve never heard anyone concerned they might loose a corporate grant. I have heard lots of people, more-or-less continuously, worrying that if their experiment doesn’t work out they won’t be able to get their PhD, land a job, or get tenure. There is enormous pressure to find something significant, to find an effect, and it matters not at all the political ramifications of that effect. So if you are worried about Monsanto buying off scientists to say GMO are safe to eat, don’t be. Convincing data that GMOs are somehow unsafe to eat would be of enormous significance, completely rewriting what we know about genetics, and would come with huge professional rewards. In my opinion, you should be more concerned that some new study showing that X, Y or Z makes plants grow bigger or yield more is actually the result of fervent, wishful thinking on the part of a grad student desperate for publishable data.
So what’s the solution? There has been a lot of talk in the academic community about making it possible to publish negative results and provide funding to regularly attempt to replicate previous studies. I hope these changes go into effect, as they could make an enormous improvement in the reliability of new findings.
In the mean time, you, as a concerned gardener, should take information supported by only a single, isolated study with a big grain of salt, particularly if it seems to contradict findings from other research. If you go to scholar.google.com and start searching around, make sure you read as much of the research on the topic as you can, so you can differentiate between the intriguing new research that may well be proved wrong and reliable findings that have been sustained by several independent researchers. And always remember that while the scientific process is far from perfect, it is still the best we’ve got.
The end of August brought an unseasonable rain- and windstorm to the Puget Sound region. We had some spectacular tree failures which I missed seeing as I was out of town. But one of our Facebook group members, Grace Hensley, was on the ball and took some great photos of a fallen purple-leafed plum. The first thing you see is the complete lack of a stabilizing root system.
“Rootless” purple leafed plum
Now look at the base of the trunk, which is actually a massive circling root that has girdled the trunk over time.
A big wooden doughnut
By now you must be able to see the orange twine extending from the base of the tree to the soil. Yes, those are the remains of the balled-and-burlapped clay root ball that was planted many years ago. Commercial landscapers will assure you that tree roots can grow through the burlap and establish. And this is sometimes true, as in this case.
But what doesn’t happen when the whole B&B mass is plopped into the ground is that circling woody roots aren’t discovered and corrected. Over the decades what started as a small circling root grew bigger and bigger, slowly squeezing the trunk and preventing it from developing girth at that point. It’s kind of like a blood pressure cuff being pressurized but never released.
Trunk growth was prevented by the girdling root. The broken part here used to be in middle of the wooden doughnut.
In time, the constricted point becomes so unstable that the tree breaks. Look are how small the trunk that’s still in the ground is compared to the trunk of the tree itself. Windstorms are often the final push these failing trees need.
How long before this neighboring tree fails, too?
Commercial landscapers say it’s too costly to remove the twine and burlap and clay surrounding the roots, not to mention doing any of the corrective root pruning that might be needed. It’s easier to just plant the whole thing and cross your fingers that the tree lives past the warranty date. This is what happens when you consider a tree as just another design element rather than a living organism.
As a homeowner, however, you can insist that your trees are planted correctly (if you have someone else do the work). Or you can do it yourself. The bare-root method (sometimes called root washing) is an emerging science and it requires thoughtfulness, but it’s certainly better than the conventional approach in terms of long term tree health.
Garden Gem is a new hybrid, poised to take the fresh market grocery store tomatoes on. Same disease resistance, same shipping quality, but with much improved flavor. Dr. Klee describes the research at his site:
The first step in a flavor improvement program starts with a simple question: what do people like and what’s in the varieties that people do like? In order to answer this question, we took a giant step back to “heirloom” tomatoes.
Blush has been around for a few years, an open pollinated variety with a great history of breeding, since 8 year old Alex was instrumental in choosing its parent lines.
The year that the cross that created Blush was made, Alex participated in setting up crosses for our annual winter crossing list. He chose 3 of the 19 crosses to be made that year, after the other 16 had been established (by a PhD-holding plant breeder with big plans). The striking outcome is that about 90% of the value from that year came from Alex’s 3 crosses. The progeny from his crosses continue to permeate most everything we are doing.
Both have something in common in that one of the progenitors for each is a variety called Maglia Rosa.
Note also the meatiness of Garden Gem … I think it will make a great all-purpose variety for the home gardener for canning and sauces, as well as fresh eating.
Another aspect, which you can’t tell very well from the picture of Garden Gem, is the faint yellow striping in the skin, and some later fruits that have a hint of a nipple on the blossom end.
Top Garden Gem Next Maglia Rosa Bottom Green Tiger
Next up, another Garden Gem, followed by Maglia Rosa, and then Green Tiger. See hints of vestigal “nipple” alluded to earlier in the Garden Gem.
Currant Tomato Solanum pimpinellifolium
Cute little feller … a Currant Tomato. Actually, a different, but very close relative, and source of much research and study, since it still grows wild in the Andean mountains … PITA to pick, but great “conversation piece” when used as a garnish. Solanum pimpinellifolium
We grew these as part of a variety trial a few years back … more for the novelty. But when we did a Brix test that year, it was the highest recorded.
A little odd, since the flavor is not in the least “sweet” … coulda been just more concentrated. Dunno, really.
Aunt Ruby’s German Green Heirloom
Aunt Ruby’s German Green. One of my long term favorites. It’s a more tangy than sweet heirloom variety that stays green when ripe.
Green Zebra
Green Zebra … an open pollinated variety bred by Tom Wagner and introduced in 1983 according to Wikipedia.
Green when ripe, and with yellow striping. Dunno why most of mine this year are exhibiting a lobed shape, rather than perfectly round.
I may have to buy new seeds next year.
Garden Treasure
Another hybrid from the research lab of Dr. Harry Klee of the University of Florida. This one is named Garden Treasure.
I don’t have any information about its progenitors, like its companion Garden Gem.
Beautiful, baseball-sized fruit. Very slight indication of green shoulders, and with the same faint yellow stripe as Garden Gem. Also a heavy fruit, very meaty.
And very good flavor. Pretty good balance between tart and sweet. I can see these being popular with fresh market growers.
I sourced the seeds from Dr. Klee’s efforts by making a small donation to his research program at the University of Florida. The idea was brought to my attention by his colleague, Dr. Kevin Folta in this blog post.
We can look forward to new, satisfying varieties that merge the best of production traits with the historical successes that delighted the senses. These are new heirlooms, and they open an exciting peek of what is coming in plant genetic improvement.
Here are more details of the story and the individual varieties! I hope you order some seeds and give your feedback to Dr. Klee so he can build your ideas into the future of tomatoes!
I often complained about the flavorless red things that you find in grocery stores, so here was a way to support researchers working to overcome that.
And Dr. Klee is not alone. Rutgers University went about restoring the old fresh market hybrid varieties that gave “Jersey Tomatoes” their deserved reputation.
Reading through Linda’s recent article in Arboriculture and Urban Forestry “Nonnative, Noninvasive Woody Species Can Enhance Urban Landscape Biodiversity” (Arb. & UF 41:173-186) reminded me of some thoughts I had while I sat through a talk by Doug Tallamy at the New England GROWS conference back in February. As most GP blog readers are likely aware, Tallamy is the author of Bringing Nature Home. The basic premise of the book is that native insects only feed on native plants and therefore the use of exotic landscape plants will cause ecological food webs to collapse and the end of the world as we know it.
Looking at things critically, there was certainly plenty to nitpick in the talk. For example, to illustrate that insects feed more on native than non-native genera, Tallamy contrasted Quercus, a genus that includes hundreds of species distributed across the northern hemisphere, to Ginkgo, a monospecific genus (heck, a monospecific order) with a limited native range in China. Tallamy also compared the food value for birds of seeds of five native shrubs with five Asian exotics. The North American plants all had higher nutrition, which leads to one inescapable conclusion: If you’re a bird-lover in Asia you need to plant more exotics from North America.
But, as I said, those items are nitpicking. In an apparent effort to appease critics, Tallamy addresses the question of whether it’s ever OK to plant exotics. He says yes, but think of them as “statues” – nice to look at but devoid of any ecological value – and then put up a slide of a landscape with a bunch of statues photoshopped in. All analogies break down eventually but the ‘exotics as statues’ model fell apart before the slide hit ever the screen. First off, native insects, birds, and other wildlife do utilize nonnative plants and I’ll refer you to Linda’s review and her 100+ citations on that point. But just as importantly, nonnatives can also provide many of the same environmental benefits as native plants. Statues, on the other hand, don’t cool buildings, sequester carbon, reduce stormwater run-off, and create vertical structure and cover for wildlife – OK, statues provide perches for pigeons, but that’s about it. Landscape plants, and trees in particular, can provide a myriad of ecological services – but they can only provide these functions if they are alive to do so. Despite the intuitive appeal of, “Native plants are adapted to our local environment”, in many urban, and even suburban, environments this is simply not true due to urban heat island effects, top-soil removal, compaction and other site disturbances.
In his talk, as in his book, Tallamy demonizes the typical suburban landscape showing a photo of an expansive lawn with a lone Bradford pear tree. OK. Is the problem here the pear? If we changed the pear to, say, a lone shagbark hickory would anything change dramatically? No, but this does bring me to a point of agreement with Tallamy. The fundamental problem we face in our landscapes is lack of diversity; not only species diversity but also structural diversity and age class diversity. If we can build diversity and generate ecosystem services with natives; great, go for it. But we need to understand that our list of suitable native trees is shrinking (as an aside, ignore Tallamy’s recommendation to plant green or white ash if you live in eastern North America). Vilifying, or even banning, nonnatives will ultimately reduce diversity in urban and community forests and their ability provide ecosystems services, not enhance it.
Doubling of flowers — the development of extra petals — is a common mutation, and often beloved by gardeners. Sometimes double forms of flowers become so popular that gardeners hardly recognize the single flowered, wild-type. Wild roses, for example, have just 5 (or, in once case, 4) petals and look totally different than the extra petal flaunting varieties familiar from gardens.
Rose glauca, like other roses before human breeders got their hands on them, has only 5 petals
Doubling usually happens when gene expression gets mixed up and bits of cells that were destined to develop into anthers develop into extra petals instead. Sometimes a single mutation makes a dramatic change all in a go, but more often, the path to a double flowered cultivar starts with something like this:
Iris x norrisii with three ugly little petaloids full of potential
Here we have a flower of Iris xnorrisii (formerly known as x Pardancanda norrisii) with the usual six petals, and three “petaloids” — anthers that are stuck in an ugly transition between anther and petal. This is a seedling in my garden this year, and I’m going to grow out lots of seeds from it — hopefully some of them will get past the petaloid stage to full on extra petals and hey presto, a double flowered variety will be born!
