Bert Cregg

Friday Quiz: Spruce brown-out?

We’re beginning to see signs that we may be getting a lot of calls on spruces this year similar ones we experienced a couple of years ago. Homeowners and landscapers are calling in with reports of brown ‘growths’ on spruces – particularly white spruce and some on Colorado blue spruce. The growths can be quite noticeable, even from a distance and cause trees to take on a brownish cast; usually most prevalent on the lower 2/3^rdsor so of the crown. What’s going on?

Note: I also discuss this problem in my article in this week’s MSU Extension Nursery and Landscape CAT Alert – but don’t go there ‘til you’ve chimed in here. Otherwise we call that ‘not in the spirit of the challenge’.

Killing with Kindness

With the advent of Spring comes a myriad of calls on distressed plants from homeowners, nurseries and landscapers. One of our better tree service companies (I’ll call the owner/operator ‘Mark’ to protect his clients’ identities) in southeastern Michigan called with a series of problems this spring so I decided to take drive over and get a first hand look. We looked at several problems on plants ranging from trees to ground covers but there soon emerged an consistent thread: overwatering. Plant problems related to overwatering and poor soil drainage are among the most common landscape issues I see year in and year out. The stops I made with Mark last week were typical. Mark works in several very affluent suburbs around Detroit (I know readers around the country don’t associate Detroit and affluence, given our recent press, but there is still some serious money in the area). Some of Mark’s clients spend up to $20,000 per year just to maintain the trees and shrubs on their property – that’s not including lawn maintenance. Needless to say, these folks want everything perfect. In their effort to have their landscape look more perfect than the neighbors, the homeowners and their gardeners often go overboard – especially with irrigation. One of the things that caught my attention during our site inspection was recurring issues with Norway spruce. For the most part, we regard Norways as a cast iron plant and one of the last trees with which we’d expect to have problems. Yet we saw several instances were established specimens were suffering needle die-back and declining.

In each case the trees were irrigated in situations where they would likely grow well without supplemental watering. But the trees were surrounded by ground covers or annual beds with heavy soils that were heavily irrigated. Problems usually increased on down-slope positions.

The solution? Back off the irrigation. Everyone knows trees need water, but roots their roots also need oxygen. At one site we visited, the homeowner already had his gardener running the irrigation system – in April! This is truly killing with kindness. Most established landscape trees, shrubs and perennials in this part of the world need little, if any, irrigation. Newly planted trees and shrubs need an occasional (weekly to bi-weekly) drink in the first year and some follow-up the second year. After that they can manage most years on our rainfall. In the end, a lot comes down to design. Establish thirsty annual beds where they can be irrigated without drowning hardier trees and shrubs.

Selling dawn redwood

As with last week, this past week and weekend were largely occupied by my role as a faculty advisor for the MSU Horticulture club. This weekend was our annual Spring Show and Plant Sale. Each year our undergraduates commandeer the Horticulture department’s conservatory, bring in a boatload of plants, pavers, turf and mulch and design and install a landscape. It’s actually quite a process to watch. http://www.youtube.com/watch?v=4NTPzB6YVSk
In addition to the Spring Show the Hort Club puts on a plant sale, which is the group’s principle fund-raiser for the year. My duty station for this year’s plant sale was working outside in the tree sales yard. For the record, retail is not my thing but, hey, it’s for a good cause. The star of our tree sale this year was a container-grown 14’ dawn redwood (Metasequoia glyptostraboides).

For those not familiar with this tree, dawn redwood is an incredible tree. It’s a deciduous conifer, similar in many respects to bald cypress (Taxodium distichum) but with a finer, more refined character. Metasequoia is considered by some to be a ‘Living fossil’, similar to Gingko biloba. The genus Metasequoia was originally described in 1941 from Chinese fossils from the Mesozoic era. Although local people in China knew the tree and used it as an ornamental, living trees were not formally described by botanists until 1948.

Dawn redwood is well adapted to wetter sites

Seed collected by Arnold Arboretum in the late 1940’s were distributed to universities and arboreta and this attractive, fast-growing tree found its way into the nursery trade. Ironically, millions of Metasequioa have been planted as ornamental trees but the species is considered critically endangered due to loss of its native habitat in China. Dawn redwood is extremely fast growing and some trees planted in the U.S. from the original collections in the 1940’s are reportedly 3’ in diameter.

Dawn redwoods on MSU campus

So, how did I fare in nursery sales for a day? Put it this way, I better hang on to my day job; retail is still not quite my thing – though I did move the dawn redwood and got to spend a good bit of my weekend talking about this awesome tree.

Going for the Gold

What do you get when you combine 900 wildly enthusiastic undergraduate students from 70 colleges and universities with 29 horticultural competitive events in a landscaping Olympics? The marvelous mayhem of the PLANET (Professional Landcare Network) Student Career Days. Last week, three of my colleagues; Brad Rowe, Tom Fernandez, Marcus Duck, and I traveled to Atlanta with 15 Michigan State University Horticulture students to compete at the 34^th annual PLANET student Career Days hosted by Chattahoochee Technical College. The Student Career Days incorporates an array of activities including tours, workshops, speaker presentations and a career fair. But the unquestioned highlight of the event is the student competition. Students compete in 29 landscape horticulture events ranging from arboriculture to computer aided landscape design. Some events require physical skills such as paver construction and landscape installation; while other such as plant identification and sale presentation test the student’s plant knowledge or interpersonal communication skills. The logistics for the host school and event sponsors is truly staggering. For example, in the Landscape Installation event, 50 three-person teams are given a 12’ x 20’ plot of ground, identical landscape plans, and identical sets of plant materials (a 15 gallon tree, shrubs, annuals, sod) and given 2 hours to complete the installation. Likewise, in paver construction and wood construction, 50 two-person teams are given identical supplies, tools and a design and must complete the project in less than two hours. Awards are presented to the top three students in each event and the top ten teams overall. Beyond the awards, however, the program offers tremendous opportunities for student to network with industry leaders, meet and compete with students across the country, and challenge themselves and build confidence. We Garden Professors are sometimes given to being a bit curmudgeonly but spending a few days at this event will definitely restore ones faith and enthusiasm in the next generation.
For the record; Chattahoochee Technical College was this year’s SCD Champion followed by perennial powers BYU-Provo and BYU-Idaho. Michigan State was 10th.

Mitch Zost tackles tree climbing in the Arboriculture event

The Lanscape Installation event is the final and culminating event of the Student Career days. Think of the 4 x 400 relay with shrubs and annuals…

Zeke Kadish negotiates the treacherous Truck and Trailer course.

MSU Horticulture faculty members Brad Rowe, Tom Fernandez, and Marcus Duck capture the action for posterity.

Joel Franken found out that accidents can happen during irrigation assembly.

Getting Loaded

Spring is off to a warm and fast start here in Michigan. March was unseasonably warm and the past week or so has seen temperature 20 degrees above average or more. Needless to say this is pushing all of our landscape trees and shrubs. Forsythia and saucer magnolia are in full bloom, at least two weeks ahead of schedule. The warm weather also has us scrambling to get some research projects in the ground as well. Today I was working with members of my lab to install a trial to look at the relationship between fertilization in the nursery and subsequent of shade trees in the landscape. For the past two years we’ve grown Acer miyabei (‘State street’ maple) and ‘Harvest gold’ Linden trees in 25 gallon containers as part of a trial on controlled release fertilizer. Interestingly, in the nursery we saw a significant increase in chlorophyll index and foliar nitrogen with fertilization (no surprise) but no difference in caliper or height growth (somewhat of a surprise). This indicates that in the nursery, fertilization induced ‘luxury consumption’ or an uptake of nutrients beyond what the trees need to meet their growth requirement. This observation provided the opportunity for our current, follow-up study. In the forest nurseries there is a growing interest in the practice of ‘nutrient loading’ seedling trees before they are lifted. Forest nursery managers deliberately induce luxury consumption by fertilizing late in the season. At this time seedlings have set a hard bud and won’t grow but can take up additional nutrients. Numerous studies, particularly by Dr, Vic Timmer and his associates at the University of Toronto have shown that nutrient loaded seedlings will outgrow standard seedlings when out-planted on reforestation sites; even though the seedlings are the same size when transplanted. How does this apply to large-caliper shade trees? We don’t know. There are certainly some underlying commonalities that are intriguing. Nutrient loaded forest seedlings have an advantage when planted on tough sites where follow-up culture is minimal – basically the seedling has to get by initially with its own energy reserves and resources. Shade trees planted as street trees often face the same hardship; once planted they may receive little or no after-care beyond an initial watering. Could nutrient loading provide a better internal nutrient reserve and jump start the re-establishment process for street trees like it does for the smaller forest cousins? We should gain some insights this summer and next.

Love in Broom

Recently, Rebecca Finneran, an MSU Extension Educator from the Grand Rapids area sent me a cool photo. The tree is a large Norway spruce near the Kent country Extension office.

This is a great example of witch’s broom. Witch’s brooms are growth anomalies that occur on various trees, most commonly conifers, Brooms can be caused be a variety of factors including diseases, aphids, environmental stress and random mutations. In some cases the growth defect is only present when the casual agent, say, a pathogen is present. In others, however, the growth mutation can be propagated by grafting scion wood from the witch’s broom onto a regular rootstock. In fact, this is the origin of many forms of dwarf and unusual ornamental conifers. Because of this, brooms are often a prized commodity and ‘Broom hunting’ is an active past-time for conifer enthusiasts such as members of the American Conifer Society. ACS members that find their first brooms are sometimes referred to as ‘Baby broomers’. Broom hunters are a focused lot and have been known to screech to a halt on major interstate in their relentless pursuit of conifer conversation pieces. So keep an eye out for brooms – and broom hunters!

With the late Chub Harper and the ‘Merrill broom’ tree at Hidden Lake Gardens, Tipton, MI

An evolving view of plant nutrition

One of the hallmarks of science is that our view of the world evolves and changes as new evidence comes to light. When I was a grade-schooler following the Apollo missions, for example, I knew all the planets in order from Mercury to Pluto and how many moons each one had; Jupiter was the champ with 12. Today, Jupiter has as many as 63 moons depending on who’s counting. And Pluto, let’s not even go there. Likewise, our view of plant science has changed over the years. As I’ve mentioned before, when I took introductory Botany as an undergrad thirty-some years ago we learned that there were 16 essential plant nutrient elements. Since then we’ve learned that nickel is also essential at least for some plants.

If you took your plant science more than 10 years ago, you also learned that nitrogen is taken up from the soil as either ammonium or nitrate. This view is now being revised due largely to evidence from the ecological literature. Ecologists have found that in northern boreal regions where soil temperatures are cold and mineralization and nitrification rates are low, plants will take up intact amino acids from the soil (Nashholm and Persson, 2001; Kielland et al., 2006). Recent studies have extended these observations to temperate forests (Gallet-Budynek et al., 2009) and horticultural crops. (Ge et al., 2009), indicating that a range of plants may be able to derive a portion of their N requirements directly from organic sources.

So what does this have to do with the Garden Professors and the science of landscape horticulture? First off, this is pretty cool stuff and certainly will cause a lot of re-evaluation of some established paradigms. From an applied perspective, fertilizing with amino acids and related organic source has some potential benefits. In warm, well-aerated soils, nitrate-N predominates. When plants take up nitrate, it must be reduced via nitrate reductase and nitrite reductase before it can be assimilated into amino acids. These steps require metabolic energy. In theory, amino acids could bypass the reduction and assimilation processes and provide a more efficient means of fertilization. At this point, most of the scientific focus is on quantifying how much organic N can be directly taken up from the soil. Evaluating efficiency of uptake and utilization is a couple steps down the road. Amino acid fertilization could potentially provide another benefit over nitrate fertilization by reducing nitrate leaching.

Of course there’s a potential downside as well. A quick Google search of ‘amino acid fertilizer’ reveals sites shilling all manner of concoctions for fertilizing plants; many of dubious value. One of the first sites I hit proclaims that, unlike inorganic fertilizers, their product provides the 70 elements needed for plant growth. Seventy?! Well that’s close to seventeen. Point is be prepared for an ever increasing barrage of claims about organic fertilizers. There is no doubt that compost and similar organic sources can provide essential plant nutrients and effective fertilizer sources. As always, however, be skeptical of spectacular claims and secret, proprietary ingredients and pay close attention to the cost of amino acids compared to conventional fertilizers. There is some science here; clearly many plants have the capacity to take up amino acids directly. Beyond that we’ve still got a lot to learn.

Gallet-Budynek, A., E. Brzostek, V.L. Rodgers, J.M. Talbot, S. Hyzy, and A.C. Finzi. 2009. Intact amino acid uptake by northern hardwood and conifer trees. Oecologia 160:129–138.

Ge, T., S. Song, P. Roberts, D.L. Jones, D. Huang, and K. Iwasaki. 2009. Amino acids as a nitrogen source for tomato seedlings: The use of dual-labeled (13C, 15N) glycine to test for direct uptake by tomato seedlings. Environmental and Experimental Botany. Volume 66: 357-361.

Kielland K, J. McFarland, and K. Olson. 2006. Amino acid uptake in deciduous and coniferous taiga ecosystems. Plant Soil 288:297–307.

T. Näsholm and J. Persson. 2001. Plant acquisition of organic nitrogen in boreal forests, Physiol. Plant 111: 419–426.

Art, Science, and Faith

First of all, who we are and what we do. All of the Garden Professors are in the business of the science of Horticulture. What’s Horticulture? The standard definition of Horticulture is the art and science of tending a garden. Horticulture is clearly more than science but science is the foundation and underpinning. For anyone that needs convincing that Horticulture is an art as much as a science I suggest the following exercise. Go to a major research university and wander through their Botany or Plant Biology greenhouses. Observe the plants. They look like crap. The people working there are on the cutting edge of plant science; they sequence genes, they elucidate biochemical pathways but they can’t grow a plant to save their lives. Now wander through the Horticulture greenhouse; plants are thriving, flowers are blooming. What’s the difference? The horticulturalists not only have the science, they have the art. There is no denying that art and intuition play a role in growing plants, especially in ornamental horticulture where we deal with hundreds of species and cultivars, each with its own subtleties and nuances. But as educators, especially public funded educators, how do we teach intuition? It’s very difficult. What we teach are principles developed through systematic scientific inquiry. How do we know there are 17 essential elements needed for plant growth? Repeated experiments over the years. And our knowledge continues to evolve based on the scientific method. I’m old enough that I learned 16 essential elements as an undergrad; the need for nickel by some plants had not yet been established. As extension educators our role is to disseminate science-based information. For some of us that phrase is even in our job description. We can try to impart our experience and intuition but it’s a difficult thing.

It can be especially difficult when we deal with alternative systems for which a long-term knowledge base may be lacking. Despite perceptions to the contrary, we are not apologists for the status quo. Overuse and misuse of pesticides and fertilizers are rampant, especially in ornamental horticulture. A lot of our current research and extension programming deals with reducing water and nutrient usage to reduce run-off and to reduce leaching. I spend a lot of time telling growers things they don’t really want to hear. How do we know growers are potentially impacting water resources? Because we and others have done the scientific research. We’ve set out plots, we’ve fertilized, we’ve sampled leachate, we’ve measured run-off. And we’ve conducted extension programs teaching growers that they can back off fertilization and irrigation rates without reducing crop growth.

Where we get concerned is that some assume or take on faith that because a nutrient source is ‘organic’ or ‘natural’ it’s automatically better or safer for the environment. Is the nitrate from Chilean nitrate less likely to cause blue baby syndrome then nitrate from ammonium nitrate? Dr. Corey Reams developed his principles as revealed to him through divine revelation. Unfortunately most of us are not blessed with such experiences. Instead we rely on systematic scientific investigation to develop knowledge that we share with our clients. Personally I do not believe that faith and science are mutually exclusive. Some of the most brilliant scientists I have met in my career have been people of deep and abiding faith. But we need to keep each in its context. Science is knowledge gained through systematic inquiry. Faith is a belief system. The central tenets of most Christian denominations are stated in the Nicene Creed which begins, “We believe in one God…” Note it doesn’t start “We know…” or “We can prove…” In their liturgy Catholics, “proclaim the mystery of faith; Christ has died, Christ is risen, Christ will come again.” Not only can they not prove these things they celebrate the fact that it’s a mystery. Faith does not demand proof. Science does.

Cool tree App for i-Phone users

I’m preparing to give my Woody Plant Physiology students their first opportunity to flaunt their new-found knowledge (aka Exam one) so only time for a short post.

As my fellow Garden Professors are aware, I am among the least tech-savvy people roaming the halls of academia these days and was long ago declared roadkill on the information superhighway. However, I recently found out about a new App for the i-phone that could lure me back into the 21^st century.

Programmer Brett Camper has developed an i-Phone app called ‘Trees Near You’. The App is based on a street tree inventory for the City of New York and allows users to view maps of over 500,000 street trees. For each tree users can look up info about individual trees including their size and estimated environmental and economic benefits based on energy savings and storm water retention. The App also links to Wikipedia pages that provide more info on the tree’s botanical characteristics. For more info, including a QuickTime movie demo, go to: http://www.treesnearyou.com/

While it may be easy to quibble with particular estimates of tree values or a particular bit of info from Wiki, there is no arguing this is pretty cool stuff. Hopefully other App writers will be inspired and Trees Near You-type Apps will start appearing for other cities. This is a great educational tool and a great way for urban and community forestry programs to promote the value of trees where we live.

A rose by any other name…

This past week I got to spend three days doing one of my favorite things; talking about conifers. Wednesday I was a last-minute guest lecturer for a landscape design class and Thursday and Friday I did my ‘Conifers for Connoisseurs’ talk for our MSU Extension ‘Plants of Distinction’ program. One of my favorite conifers and one I often recommend as a large specimen tree is Alaska yellow-cedar (the name I learned in Mr. Chance’s Botany class at Olympia High School) or Nootka false cypress (the usual common name for the tree in this part of the world). Notice that I didn’t give a scientific name, like a good garden professor should. The reason? I’m not 100% sure what the scientific name for Alaska yellow cedar is any more.

Xanthocyparis nootkatensis at Daisy Hill Farm, DeWitt, MI

Prior to 2000 it would have been easy: Chamaecyparis nootkatensis. Then a team of international scientists including members of the Kew Royal Botanic Gardens and the Missouri Botanical Garden discovered a rare conifer in northern Vietnam, which was previously unknown to science. The new species was described in a 2002 article by Farjon et al as Xanthocyparis vietnamensis. A conifer still unknown to science at the end of the 20^th Century, that’s pretty cool. But, in addition to describing and naming the new species, the authors’ also reclassified Chamaecyparis nootkatensis with the new species as Xanthocyparis nootkatensis. While this news was mildly disappointing to those of us who love the tree and thought Chamaecyparis nootkatensis was about the coolest scientific name ever, the name change was not entirely surprising. Within the genus Chamaecyparis, nootkatensis was always the proverbial red-headed step-child. At one point the species had been grouped in the genus Cupressus. The change to Xanthocyparis also required a change for Leyland cypress, an intergeneric hybrid between Alaska yellow cedar and Monterey cypress (Cupressus macrocarpa). Under the new nomenclature ×Cupressocyparis leylandii becomes × Cuprocyparis leylandii.

Now, as if all this weren’t confusing enough, subsequent work by Damon Little based on molecular markers groups all of the Cupressus species in North America and the two Xanthocyparis species under one genus, Callitropsis. Little et al’s re-classification and rejoinder by Mill and Farjon (2005) demonstrate the schism which has developed between taxonmists that rely heavily of cladisitcs and molecular tools and those that rely on morphology and evolutionary relationships. Their debates are far testier than any barbs traded between Linda and the Brothers Horvath. Check out this link for a taste of the action:

http://urhomology.blogspot.com/2009/03/myths-that-evolutionary-taxonomists.html

Xanthocyparis nootkatensis at MSU Horticultural Gardens

So what about us poor horticulturists and foresters who just want to know what to call the damn thing? I suspect the taxonomic battle lines will deepen before anyone offers a peace offering. And this will extend far beyond Xanthocyparis (syn. Callitropsis). Get used to seeing lots of synonyms next to scientific names in the future. Remember when you took your first Botany class and learned we used scientific names to eliminate confusion over common names? Sigh… Alaska yellow-cedar sounds pretty good to me.

Farjon, A., N.T. Hiep, D.K. Harder, P.K. Loc, and L. Averyonov. 2002. A new genus and species in Cupressaceae (Coniferales) from northern Vietnam, Xanthocyparis vietnamensis. NOVON 12:179-189.

Little, D.P., A.E. Schwarzbach, R.P. Adams, and C.-F. Hsieh. 2004. The circumscription and phylogenetic relationships of Callitropsis and the newly described genus Xanthocyparis (Cupressaceae). American Journal of Botany 91(11): 1872-1881

Mill, Robert R. and Farjon, Aljos. 2006. Proposal to conserve the name Xanthocyparis against Callitropsis Oerst. (Cupressaceeae). Taxon 55(1):229-231