Tag: woody

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 2/3rds or 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.

Oh, Deer…

More from our Ornamental Plant Production class tour across the state.  One of our stops was James River Nurseries, Inc.  Owner Mike Hildebrand has a built a unique and diverse business – they not only grow but do landscape design-build-install, all in the huge market of central and northern Virginia and beyond.

Here’s some arborvitae that spent the past few weeks at one of their job sites north of Richmond, waiting to be planting.  They’re now back at the nursery.  I was going to make this a quiz, but it’s unfortunately just too obvious.

deer nibbles

Wow. Poor things never even made it into the ground.

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.

Age

This time of year is very exciting for the students in my plant propagation class because now is when they all get to try grafting.  In particular, they get to place buds from an apple tree onto a rootstock.  There is nothing like placing a bud from one tree onto another to make a person feel as though they’re a horticulturist (NOT HorticulturALIST — that’s not a real word).  Especially if that bud successfully grows on the plant where it was placed and produces a happy new tree — What a warm fuzzy feeling!

There are all kinds of things that a rootstock can offer to the bud placed on it.  The rootstock can make the tree a dwarf, it can be resistant to certain diseases which the bud isn’t, it can even add some degree of cold hardiness.  In return, the bud produces a cultivar that the grower wants such as ‘Honeycrisp’ apple.  Additionally, the bud also offers an older tree.  This probably doesn’t make sense at first, so think about it for a second or two.  The bud that was grafted onto the rootstock came from a mature tree and so it may be more mature than the rootstock (which may have come from a seed — if the rootstock came from something besides a seed — like cuttings — then the rootstock may also be quite mature).  Because the bud from which the top of the tree will grow is more mature than the base the tree will usually come into bearing sooner than if it were grown from seed.

Tree age is a funny thing.  Though you wouldn’t expect it, the base of a tree is actually the youngest part of the tree physiologically while the older portion of the tree is at the top from which most new growth comes.  The reason for this is that the bottom of the tree was laid down first as the tree first emerged from the soil and so the bud from which that growth came hadn’t had the chance to age much yet.  After a few years of growing up the terminal bud developed more and more “age” and so the top of the tree is more mature.  Confusing?  It confuses me too — and I’m oversimplifying things quite a bit here.  Making it even worse, no two tree species seem to age in exactly the same way.

Edgeworthia!

Some of my favorite plants are those that “do something” when little else is.
Do we really need more June-flowering perennials? No!
Well, yes. Never mind.

Edgeworthia chrysantha – “Paperbush” is the common name – is a deciduous suckering shrub , native to China. It usually maxes out around 4′ to 5′ tall and as wide.  The large, matte bluish-green leaves resemble those of Magnolia virginia in shape and are also a bit silvery on the underside.  But that’s not what we’re here for…

An oooh-aaahhh-worthy specimen at the Hahn Horticulture Garden, Blacksburg, VA.

Furry, silvery flower clusters dangle like earrings from the cinnamon stems throughout the winter, getting larger by the month.  

Then by late February or March, they open up, all golden and waxy, emitting a light, sweet fragrance on sun-warmed days.


Blooms at Pine Knot a few Springs ago…

Edgeworthia is ideal for the deciduous woodland environment. Hellebore specialists Dick and Judith Tyler of Pine Knot Farms (Clarksville, Virginia), situate theirs among drifts of spring bulbs and, of course, Hellebores. It’s a soul-stirring sight in March.

I believe the hardiness of Edgeworthia may be underestimated, especially if you go to a little effort to select the right microclimate.  Dr. Dirr lists it as Zone 7 to 8(9). Having enjoyed them at the JC Raulston Arboretum during my doctoral work at NC State (Raleigh, North Carolina; Zone 7b), I found Edgeworthia was little-know here in the Blue Ridge (solid Zone 6, alledgedly 6a).  We ordered some in for our Garden and Hort Club’s 2007 plant sale held in late April – despite my pleading and mark-downs, they didn’t generate much interest from shoppers as they were out of flower. We planted the left-overs in a fairly protected position on the North side of our garden pavilion, and they’re thriving. Snow was heaped up around them throughout January and February and we’ve gotten well into the single digits complete with howling winds a few times.  Despite this rotten winter, they look better than ever, ready to burst into bloom any day now.  Readers, please weigh in: Had any success with it in Zone 6?  And why isn’t this fabulous thing more prevalent in the trade? 

Protecting existing trees – what a concept!

I just got back from a trip to Pullman where I guest lecture once a year for the Landscape Plant Management class.  It’s also a chance to get some new photos for my Wall-O-Shame.  Here’s my latest:

Pin oak (Quercus palustris) doesn’t drop its leaves in the winter – instead, they hang on until the following spring.  So it’s really easy to see which part of this tree is alive (i.e., has last year’s leaves).  It’s apparent that most of the crown has died, with only some lower scaffold branches remaining.

How did this happen?  Take a look at how new that concrete is around the base of the tree (and how small the tree well is.  This construction was done in 2004:

Note the complete lack of root zone protection.  Not only has the majority of the tree’s fine roots been destroyed in preparation for pouring concrete, but only a very small space under the tree is “protected.”  I guess the cup at the base represents the irrigation system.  To top it off, this construction was done in August, when coincidentally I was there as well.  It was blistering (as it usually is in the summer in eastern Washington), and the remaining leaves on this tree were wilted:

So why would anyone be surprised when, 6 years later, this tree looks like crap?  And why doesn’t WSU insist on tree protection standards when construction bids are submitted?

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 21st 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 20th 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

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