OK, I know we gave you a tough assignment for the weekend, so I want to post something fun as well. (Think of this as dessert after your healthy meal!) Take a look at the photos below:
This hedge is regularly sheared and no one part of it has been maintained any differently than another part. Both sections of the hedge face east, and the damage is anywhere from 2 to 4 feet from the ground. What do you think has caused the damage?
Explanatory photos reveal all on Monday!
Recently I was asked to comment about a rash of e-mails floating around cyber-space concerning the toxicity to dogs of mulch made from crushed cocoa bean hulls. Cocoa mulch is by-product of cocoa production. The dark brown mulch is aesthetically and aromatically pleasing, giving the garden a rich, chocolately scent. Since theobromine, a naturally occurring compound in chocolate is toxic to dogs, the internet is now filled with cyber-legends of dogs eating cocoa mulch and keeling over dead.
According to an article published in the Journal of the American Veterinary Medical Association (JAVM June 1, 2006 p. 1644), cocoa bean husks can contain up to 2.98% theobromine. The JAVN article state “no reports of lethal toxicosis from ingesting this mulch have been filed with the ASPCA Poison Control Center this year (2006). In 2004 and 2005, 16 reports of single exposure to the mulch were received, none resulting in death.”
The ASPCA posts this comment regarding cocoa mulch on its website:
“Dogs consuming enough cocoa bean shell mulch could potentially develop signs similar to that of chocolate poisoning, including vomiting and diarrhea. In cases where very large amounts of mulch have been consumed, muscle tremors and other more serious neurological signs could occur. To date, the ASPCA Animal Poison Control Center has not received any cases involving animal deaths due to cocoa mulch ingestion. One key point to remember is that some dogs, particularly those with indiscriminate eating habits, can be attracted to any organic matter. Therefore, if you have a dog with such eating habits, it is important you do not leave him unsupervised or allow him into areas where such materials are being used.”
It should be noted that processed cocoa mulch may contain much lower concentrations and some manufacturers market cocoa mulch that is ‘Pet safe’. Consumers should look for products that are tested and certified theobromine free.
As always, I stand by my recommendation to use locally processed wood products such as ground hardwood bark and ground pine bark. Plants grow well in these mulches, which are typically among the most cost-effective and natural looking (to me, at least) mulches available, and they are renewable and help support your local economy.
So back in September my department head (who is, for all intents and purposes, my boss) handed me a New York Times article (http://www.nytimes.com/2009/09/24/garden/24garden.html) about the grass at Harvard which is now being managed organically. We share the opinion that many organic techniques, such as compost tea, are “Voodoo Science” (that’s a term I stole from Mike Dirr) and so she thought I’d be interested in the techniques that Harvard was using. She didn’t say it explicitly, but I think she thought I’d get a laugh out of it. And I did….Along with a funny feeling in my stomach.
After looking at the article I just couldn’t resist going to Harvard’s website (http://www.uos.harvard.edu/fmo/landscape/organiclandscaping/) and finding out all of the stuff that they’re doing to make their grass look wonderful. And, to be honest, much of it is great. They’re aerating more, they’re adding compost to the soil, they’re using fewer pesticides. All of which I wholeheartedly agree with.
And then they’ve got this whole compost tea thing going on. In fact, they actually include information on how to make a compost tea brewer and different recipes for these compost teas.
For the uninitiated, compost tea is a mix of water along with other things — such as a carbohydrate source (like molasses, or flour, or sugar, etc) and maybe even a little bit of organic fertilizer — into which a “teabag” (usually something like a burlap sack) is dipped which contains compost. Air is usually bubbled through the mixture, in part to reduce the likelihood of bad bacteria, like E. coli, infesting the mix (research has shown that this doesn’t work). Supposedly the good microbes from the compost start growing in the spiked water producing a “tea” which is packed with microbial goodness for your plants. The microbes are supposed to revitalize the soil as well as, potentially, helping it to ward off plant diseases.
Bullpucky.
This isn’t to say that I don’t think soil microbes are important because I do — they’re vitally important! But why is it that some people think compost tea is needed to add them? As a researcher and professor I’m supposed to try to stick to saying what the research supports. Following those rules I’d like to add to a comment that Linda made the other day. The research currently shows that compost tea is unlikely to do a darn thing for you — at least in terms of the microbes which it adds. Compost teas, like the ones from the recipes at Harvard, will often have nutrients in them from the added compost (nutrients will leach into the water from the compost), or from fertilizers. These nutrients can obviously provide some fertility to the soil (or to the foliage). Beyond that fertility I am completely unconvinced of the value of compost tea.
So why are the people at Harvard raving? Well, it looks to me like they did a bunch of good things, incorporated one Voodoo science technique, and then attributed an inappropriate amount of their success to the Voodoo science technique. Go Harvard!
I’m going to close with an image of some roses (these are a small sample from a larger experiment) that I treated with compost tea to protect them from disease. Don’t they look nice? I have a number of researcher friends who have also tried these teas. None has had a positive experience.
I just had a long conversation with Michele Owens (of Garden Rant fame) about vegetable gardening. This isn’t one of my strong areas, either professionally or personally (I do have containers of herbs, but that’s as far as it goes). But what piqued my curiosity was her revelation that the vegetable gardening is just as full of myths and misinformation as my field of ornamental landscaping.
I’ve ventured into the realm of vegetable garden science now and then, especially in reference to having soil tests done before planting edibles (good!), the use of CCA-treated timbers (bad!), and companion planting (silly!). Beyond that I haven’t given the topic much thought.
(You know who loves you know who!)
So, readers, what gardening practices out there need to be screened through the sieve of science? Jeff and I have both written about many practices and products, but as you know our expertise is more on the ornamental side.
(Forgive my short blog today. I’ve had some kind of chest crud since last Friday and I’m still wiped out.)
Following up on Holly’s theme of “I can’t believe I get paid to do this”, last Wednesday I participated in a walk-through and inspection of the Justin ‘Chub’ Harper Collection of Dwarf and Rare conifers at MSU’s Hidden Lake Gardens in south central Michigan. The Harper collection is widely regarded as one of the premier collections of rare and unusual conifers in the world.
Harper Conifer Collection with fall color background. Photo: Jack Wikle.
A little background: Chub Harper was the former grounds supervisor for John Deere’s world headquarters in Moline, IL, an avid plant collector, and a founding member of the American Conifer Society (ACS). He acquired hundreds of rare and unusual conifer specimens around his home and eventually had to lease a nearby lot for the overflow – demonstrating that ACS also stands for ‘Addicted Conifer Syndrome’. In the early 1980’s Chub donated 300 conifers to Hidden Lake Gardens to establish the Harper collection. All of the plants were balled and burlapped by hand and shipped in three semis to Michigan. Chub continued to add plants to the collection and today the collection includes over 500 accessions.
Chamaecyparis pisifera ‘Filifera aurea’
I met Chub about 8 years ago and with his guidance and inspiration started a series of ‘Conifer Corner’ articles in the Michigan Nursery and Landscape Michigan Landscape magazine. (visit my faculty page for .pdf’s of some sample articles http://www.hrt.msu.edu/bert-cregg/pg5). Once or twice a year Chub would travel from Moline to Michigan to inspect the collection along with members of his conifer posse. To me, the most impressive thing about the walk-throughs was how absolutely ruthless Chub was in disposing of under-performing plants or plants with continual pest problems. “Time for that thing to take a ride on the chipper truck” was a favorite Chub-ism. Hidden Lake Gardens has a garden staff that could spray pesticides or prune away dead material regularly; but Chub wanted none of it. This is not to say that Chub was into organic gardening; as far as I know he had no particular aversion to chemicals. Rather, he felt the mission of the collection was education and that maintaining plants in an artificially superior condition would mislead the public into thinking some conifers were better suited than they actually were.
The Conifer posse at the 2007 walk-through. Chub Harper is 3rd from left, back row.
Chub passed away unexpectedly earlier this year and last Wednesday’s walk-through was the first evaluation of the collection without him. The conifer posse carried on, led by former ACS President Dennis Groh; Chub’s longtime friend Jack Wikle; and Sam Lovall, the landscape architect who developed the original design for the collection. We found homes in the collection for several new specimens including an Abies concolor ‘Charmin’ Chub’ and condemned a few underachievers to a ride on the chipper truck. Chub left many legacies; the most obvious and tangible is the Harper Collection and the staggering generosity it represents. Imagine dedicating half your life to acquiring and cultivating a world-class collection and then simply giving it away. Just as important, however, is the legacy he left with those who knew him, who felt his passion for conifers, and were inspired by him.
Pinus parviflora ‘Cleary’
Here’s the follow up picture from Friday’s puzzler:
As you can see, there’s a street light near the lower half of the maple. (I cleverly hid it behind the utility pole in the first photo.) The green part of the tree never received the message that days were getting shorter, since the street light is bright enough to interrupt the dark period necessary to initiate dormancy.
This is one of my favorite phenomena unique to urban environments. It doesn’t appear to hurt the tree, although the green leaves will die before the tree can scavenge their nutrients. If more of the tree were affected, I’d be more concerned.
Congratulations to Planting Oaks, who nailed this right off. And kudos to those thoughtful alternative explanations, all of which could logically have had an impact on color change.
Here’s a photo I took in Buffalo about 20 years ago. Buffalo, like many places in the northeast part of the country, has fantastic color changes in the fall. This maple seems to have changed its mind part of the way through the process:
What do you think caused part of this tree to retain its green leaves? Answer and another photo on Monday!
I just couldn’t resist posting this picture today. There are a bunch of garden gurus out there who claim that slugs won’t cross crushed eggshells. I, personally, have never seen a slug halted by them.
I know a few folks out there are starting to believe that I’m just an apologist for the nursery industry. While it’s true most of the nursery people with whom I work are hard-working folks trying to do their best to run a successful business and produce a quality crop, there are certainly some issues out there and I’ve got my share of pet peeves. One of the things really that chafes my heiney is what I refer to as “Carrot-top” syndrome in eastern white pine (Pinus strobus). White pine is one of the most commonly planted conifers in this part of the world. White pine is native throughout much of the eastern US and is an extremely fast growing tree that makes a good ornamental when planted on the right place with room to grow. It is also widely grown as a Christmas tree in the Upper Midwest as well and therein lies the rub. Many nursery producers also grow Christmas trees and many Christmas tree growers also dig nursery stock. The result? White pines that have been heavily sheared as Christmas trees end up planted as landscape trees. Once in the landscape, the upper portions of the trees will quickly resume rapid growth, with some shoots growing 2’ to 3’ or more per year; while the side shoots that had been repeatedly sheared barely grow at all. After a couple of years the net result is neatly trimmed Christmas tree with a wooly beast growing out of its top. What’s the solution? Ideally producers should identify which portion of their trees will be sold as Christmas trees and which are destined for the landscape trade. Christmas trees can be sheared to meet demands of that market while landscape trees can be pruned much more lightly to maintain a single leader and conical form but keep obvious layers of whorls. The dilemma, of course, is that growers don’t always know which trees will end up and the Christmas tree lot and which will be dug for the nursery trade. The other, more challenging problem is that, given a choice, 99 out of 100 garden consumers will choose the neat-looking Christmas tree for the landscape, unaware of the wooly mess that’s about to be unleashed in their yard. The solution? Education on both sides; making growers aware of the issue and making consumers realize that the only way to have a natural-looking white pine in your yard is to start with a natural-looking white pine.
Heavily sheared pines will retain the outline from from shearing for years while the top rages out of control.
Linda referred to my recent absence from the blog – but it was in the name of education, I swear!
Cocos nucifera, the iconic coconut palm. My office for the past two weeks. Or a Corona advertisement. You pick.
This study abroad to the Dominican Republic sent Virginia Tech students (mostly biology and natural resources majors) to the Punta Cana Ecological Foundation for the entire semester, with faculty rotating in for two-week stints on topics from ornithology to geography. My topic was “tropical horticulture”. The professor previous to my session had to cancel his trip; by the time I arrived, the un-chaperoned students had basically gone feral. Corralling them with promises of beer and French fries, I coaxed them out onto plant i.d. walks. By the time our field trip to the national botanical garden rolled around, they were blurting out plant names left and right. Made me proud!
Identification walk featuring salt-tolerant plants. That’s red mangrove, Rhizophore mangle, on the right. Feral students on left.
The ecological foundation’s shade houses, orchard, and organic veg gardens grow some of the produce for the resort and made for a great learning experience (unusual greenhouse pest problem: tarantulas). I’ll post more tropical plant pics and factoids in January – when we’ll really, really need to see them.
Morinda citrifolia, better known as Noni. Though chock full of vitamins and all manner of secondary metabolites of medicinal interest, the smell of ripe Noni is comparable to Limburger cheese left in the sun for several days. Shrieks of “NONI!!!” meant someone was about to get pelted with over-ripe fruit.