Planting trouble: multiple trees in one hole

[I enjoyed Jeff’s Valentine story so much that I thought I’d stick to the theme of togetherness…for better or worse.]

A week or so ago a reader asked about the practice of planting three or four fruit trees in the same hole.  Having not heard of this before, I checked on the web and found many “how to” pages geared to home gardeners who either want a longer harvest of a particular fruit (early to late) or a mixture of different species.  Doesn’t it sound just great, especially for smaller urban yards?

One of these sites has these written instructions: “Plant each grouping of 3 or 4 trees in one hole at least 12 to 15 inches apart.”

Now, I’m sorry, but this is just asking for trouble down the road.  Readers of this blog know that root systems extend far past the drip line, and that roots from different trees are going to compete with one another.  You’ll end up with three unhappy trees, all jostling for space and resources, just like kids in the back seat during those long car rides.

But wait! you might say.  There’s research on high density tree planting, and it’s been shown to increase fruit yield on a per acre basis!

Yes, in fact there is a lot of planting density research on many different species of fruit trees.  What’s considered by researchers to be “high density” varies, but it rarely exceeds 2698 trees/acre (6666/ha for our international readers).  Optimal and sustainable levels of high density planting are also variable, as they depend on not only species but rootstock and the crown architecture; 1214/acre (3000/ha) might be a mid-range number.  This can be converted to a per-tree requirement of 36 sq. ft. or a 6’x6’ planting area.

How does this compare to the 12-15” recommendation given earlier?  If we’re generous and use the 15” recommendation, this translates to 6.25 sq. ft. per tree or 6970 trees/acre.  The 12” recommendation would lead to a whopping equivalent of 10,890 trees/acre.  (And no, it doesn’t matter if you’re using dwarfing rootstock or not; most of the higher densities in the literature are for dwarfing rootstocks.)

You don’t have to be a math whiz to see that these densities are totally out of line with reality.  Sure, you can probably keep overcrowded trees alive with lots of water and fertilizer, but they’ll be under enough chronic stress so that pests and disease might take hold, and fruit production will likely be poor.  And it’s about as far from a sustainable practice as you can get.

More Master Gardener Fun!

Am just heading out the door for Fairfax, Virginia – part of the greater Northern Virginia metro area, with traffic that scares the pants off of us country mice. I’m doing the Master Gardener training for the Fairfax Master Gardener Association.  Their attendance is so huge, they have to split into a morning session (150 people) and an evening session (100+). Two and a half hours of training on “herbaceous plants” twice in one day – that’s a lot of yakking even for yours truly.   But what a terrific group. I led the herbaceous sessions in 2007 and was impressed at the diversity of age, ethnicity, levels of knowledge, you name it. A complete cross-section of the area, all with the common desire to learn. Merrifield Garden Center generously (and brilliantly) hosts the training in their large meeting room. Alas, after we all get worked up over the fab perennials, annuals, and tropicals, there’s not much to buy this time of year.
I’ve written about the tremendous contribution of volunteer hours that Master Gardeners make to our state.  As the budget axe drops hither and thither, Extension programs always seem to be at risk. All of the Garden Professors have noted their own state’s struggles with such. Here’s the (slightly) brighter side, though – the Fairfax Master Gardener Association receives no funding from federal, state, or local government. Just some training materials from Extension Same with most of the other associations across the state. Not much to cut, really. In turn, it was calculated that MG volunteers across the state reported 334,000 hours of service for 2009. That’s a pretty good return on very little investment from the state.  Heck, I don’t even have an Extension appointment. But I’m a believer in the MG system, and want to help in whatever way I can, even if it means leaving the peaceful mountains and driving to Northern Virginia. A bit of a bonus is there’s really good shopping up there. Heh.

An Early Valentine’s Story

In honor of Valentine’s day I have a story about love and betrayal to share….OK, maybe not….perhaps something more along the lines of branches and ants.  Same difference right?

There was once a tree that was much loved.  It was planted in a cute little corner of a street next to a historic building and was well cared for by its owners. Its many limbs rose to the sky in a seething mass which made the tree look vigorous and robust…and those who planted the tree were very happy.

Over time, however, the people who planted the tree neglected it.  The street where it was originally planted changed from a bustling center for traffic to a lonely, out-of-the-way road.  As it was ignored its branches grew together and made a mess — and nobody noticed this mess — except for a little horticulturist who had to walk by the tree every day on his way into work.

The little horticulturist was fascinated by the tree.  Not because the tree was a particularly fine specimen, no, that wasn’t it at all.  Instead the little horticulturist was fascinated by the tree because its limbs grew together so closely that they actually appeared to be grafting with one another, something that the little horticulturist would often spend hours contemplating (what can the little horticulturist say — sometimes he liked to avoid real work).


Two limbs apparently grafted together!

Then one day something terrible happened.  An evil green insect invaded the street where the tree lived, and all of the ash trees on that street had to be cut down.  Even though the tree couldn’t be infested by the insect (it was a hackberry), it was still on the list.  The little horticulturist pleaded with the groundskeepers to keep the tree, but orders were orders and the tree had to go.

But unbeknownst to the groundskeepers the little horticulturist knew one of the people cutting down the tree and asked the tree cutter to save him some of the trees limbs where they appeared to be grafted together.  And the tree cutter did, and delivered them to the little horticulturist.

But alas!  The grafts that the little horticulturist had seen were not truly grafts at all!  They were rotted out sections of trunk which had grown around each other!  The little horticulturist was crestfallen!  How could this be?  He left the decaying limbs in his office as he considered what to do next.


Hmmm…There’s no graft after all –what a mess!

Days stretched into weeks and the limbs continued to sit in the little horticulturists office.  And then, one day, from the depths of the limbs sprouted new life!  Winged carpenter ants flew around the room and into neighboring rooms!  Colleagues shouted curses and obscenities!  Graduate students were afraid to use the drinking fountain because of the masses of ants which alighted there!  The custodians took to wearing dust masks!  And, despite incessant pleading by almost everyone, the little horticulturist would not part with the limbs because he wanted to have props whenever he told the story of the day the ants took over the 4th floor.

The moral of this story is that you shouldn’t hold onto things once you figure out that they’re worthless.

Landscape design – fatal flaw

So many great answers…so many problems with this landscape!  Everyone who made a comment was spot on in their reasoning.  And each of these flaws was completely preventable with good design.  But I’m not sure I would have been able to predict the problem that I now see every week at this location:

his area is the only access point for service vehicles of any persuasion. And sometimes they DO park on top of the planting strip.  Fred’s designation of these ground covers as “Stompus flatii” was perfect!

Lesson to be learned:  sometimes it’s best NOT to have planting strips if they clash with the realities of site use.

Friday quiz – landscape design

Down the street a ways from where we live is a relatively new condo complex wedged between a hill and the street.  A narrow planting strip separates the sidewalk from the street, as shown below:

The driveway at the top of the photo bisects the planting strip and dead ends in the parking area for the condos.  I have photoshopped this a bit, for reasons you’ll see on Monday.  But this is a true representation of the landscape.

I’d originally taken photos of this area for my ongoing “why trees die” collection (since all but one died within 2 years), but there’s something else wrong in this landscape related specifically to the design.  Can you figure out what it is?

Answers and more photos Monday!

Scrambling for Answers

Yesterday a good friend of mine who works for a well respected tree company in town asked me whether I would be willing to talk about  tree conservation as it relates to the emerald ash borer.  Specifically he wanted me to make people aware of a statement produced by a group called the Coalition for Urban Ash Tree Conservation which you can find here which was produced by a number of well respected industry people and academics.  This statement basically says that we shouldn’t cut down all of our ash out of fear of the emerald ash borer but that we should, instead, treat some with various insecticides to conserve our ash.

I don’t have any major disagreement with the article, but it’s important to remember that every situation is different and that, while chemical treaments might be appropriate for one ash, another should hit the chipper.  As the emerald ash borer moves across the country we’ve got to assess what our ash are worth to us and decide when and where it’s appropriate to save them.  This is an extremely daunting task without easy answers.  The statement by the Coalition for Urban Ash Tree Conservation is good and very appropriate, but what would be even better is a guide to help people decide whether to leave trees alone, to cut them down, or to treat including all of the costs and consequences.

UPDATE:  As you might have expected, there is already a cost calculator out there — I just wasn’t aware of it.  Fortunately Katie was and left details in the comments section.  If you are interested in a calculation to figure out the cost of treating vs. removing ash go here http://www.ag.purdue.edu/entm/Pages/csadof.aspx and then click on EAB cost calculator — it’s on the left hand side.  It’s a very nice little tool!

Er, Too Much Coverage?

When botany and advertising collide.  Here we have the latest from AT&T.
The advertisement description’s in quotes.


“We open on an urban setting and see a vine begin to grow up a
pillar.”

What kind of vine?? It looks like a mutant clematis, though the leaf arrangement’s wrong, and there are no orange large-flowered ones. Oh well, let’s not be picky. At least it’s some kind of ornamental plant. We’ll call it Clematis broadbandii. Definitely non-native, though.


“From there, we see various landscapes being covered with
similar vines.”

What the…well, I guess the overpass does look better. And the city’s doing a great job keeping it out of the road.


“As the seedlings grow, they sprout brilliant orange
flowers, covering the cities, towns, and countryside’s in a spectacular
orange hue.”

Honey, drive faster. This neighborhood gives me the creeps.


This is ridiculous… I’m calling Linda Chalker-Scott! Or maybe Jeff Gillman, for a fair and balanced herbicide recommendation; or maybe Bert Cregg could suggest how to cut it back. Holly Scoggins is a flake; she’d just tuck Bounce sheets everywhere...


“Coverage is a beautiful thing. AT&T covers 97% of all Americans.”

Dear AT&T: the National Invasive Species Council will be in touch. Unless their call gets dropped.

Proposed phosphate fertilizer ban – a dissection of the criticisms

A few brave souls gave Friday’s homework assignment a good shot.  Ryan did a nice critique of the bullet points; Kenny did a little digging on WFFF, the organization behind the email; and Tom chimed in with the fact that Israel managed to do this a long time ago without impairing plant health.  Gold stars for all!

Here’s my initial analysis of the statements made, based on reading the bill (which you should do if you haven’t yet; it’s neither long nor difficult to understand):

WFFF: 1) The intent section contains scientifically inaccurate statements, creating a false precedent that turf fertilizer is a significant surface water pollutant and is not necessary for a healthy lawn.

The bill: The legislature finds that: (a) Phosphorus loading of surface waters can stimulate the growth of weeds and algae and that this growth can have adverse environmental, health, and aesthetic effects; (b) Lawn fertilizer contributes to phosphorus loading. Limits on fertilizer containing phosphorus can significantly reduce the discharge of phosphorus into the state’s ground and surface waters; (c) Fertilizer containing no or very low amounts of phosphorus is readily available and maintaining established turf in a healthy and green condition is not dependent upon the addition of phosphorus fertilizer; and (d) While significant reductions of phosphorus from laundry detergent and dishwashing detergent have been achieved, similar progress in reducing phosphorus contributions from fertilizer has not been accomplished.

LCS:There is no identification of the “scientifically inaccurate statements” in the intent section, and as far as I can tell the statements are accurate.  The WFFF statement also misdirects the reader into believing that the intent section states that “turf fertilizer…is not necessary for a healthy lawn” when in fact the section (point c) states that healthy lawns can be maintained with low phosphorus fertilizers.

WFFF: 2) It grants the authority to regulate fertilizer sales and use to the Department of Ecology (Currently, the Department of Agriculture regulates fertilizer content and registers it for sale.)

LCS:  It is unclear why this is a problem; both are state agencies.

WFFF:  3) It changes the definition of fertilizer used by the Department of Agriculture, creating confusion.

LCS:  Where is the confusion?

WFFF:  4) It is inconsistent and will be ineffective because it exempts “natural organic sources.” Organic products are high in phosphorous. The ecosystem cannot tell the difference. All fertilizer should be regulated equally.

LCS:  This is misleading.  Not all organic products are “high in phosphorus”.  Furthermore, the phosphorus in organic matter is usually bound up in compounds that must be degraded before the phosphorus is available, making organic matter more of a slow release material.

WFFF:  5) It fails to recognize the expertise of trained lawn care professionals, who should not be prohibited from providing quality service to their customers, including publicly owned golf courses, parks, and sports fields.

LCS: How is the “expertise of trained lawn care professionals” relevant to the bill, and how is this expertise not being recognized?  In fact, the bill creates increased expert oversight by working with Washington State University Extension specialists (faculty) in setting standards for applying phosphorus fertilizers based on soil test results.

WFFF:  6) As written, it bans the use of phosphorous fertilizer for forestry, house plants, shrub beds, golf courses, sports fields and other uses. It is unclear as to private commercial property.

LCS: Unless there is a demonstrated need for phosphorus fertilizer (i.e. a deficiency verified by soil testing), there is no need to use it.  The routine use of phosphorus fertilizer without establishing a need is the behavior this bill seeks to limit.

WFFF: 7) It bans the sale of phosphorous fertilizer for flower and vegetable gardens, forestry, house plants, shrub beds, golf courses, sports fields, and many other uses.

LCS: Again, unless there is a demonstrated need for phosphorus, it should not be routinely added to any garden or landscape.

WFFF: 8) It bans retailers, including farm stores and ag dealers, from displaying any type of fertilizer containing phosphorous.

LCS: This does not preclude people from purchasing it.

WFFF: 9) It fails to address the primary causes of impaired water quality. Regulating something because it’s easy without addressing root causes of the problem accomplishes nothing.

LCS: This statement fails to inform us what the “primary causes of impaired water quality” are. How do we know that fertilizer runoff is not one of these causes?

Insects and Fertilization

Linda got a few comments and questions on her post a couple of weeks ago on fertilization and insect resistance.  This is an issue I’ve been peripherally involved with over the years so I wanted to share a few thoughts.  First, the relationship between plant nutrition and insect resistance is extremely complex.  We often have difficulty predicting how a plant is going to respond to fertilization, let alone predict how an insect is going to respond to how the plant responded.  I haven’t kept up but Koricheva (2002) reported over a dozen different theories have been proposed to explain insect response to plant nutrition.  One of the factors that makes it difficult to generalize about plant/insect interactions is that various insects feed on different plant parts in different ways; some are leaf feeders, some suck sap, some bore into wood, some feed on seeds or cones.  How an insect feeds can affect its response.  To stick with an illustration I’m more familiar with, we can look at insect response to plant drought stress.  Bark beetles are widely known to key in and attack pines and other conifers under drought stress but pine tip moths prefer succulent buds and new growth and are more likely to attack well watered trees.  It’s not unreasonable to think there are similar differences with nutrition.

 

Nevertheless, as noted above, there have been attempts to come up with general theories on the effect of plant nutrition on insect resistance.  One of the most widely cited is the Growth-differential balance theory proposed by Dan Herms and Bill Mattson  (“The dilemma of plants: to grow or defend.”  Q. Rev. Biol. 67: 283-335).  A quick check on Google Scholar indicated this paper has been cited by over 1,400 other papers, which is an astounding number and speaks to its influence.  The basic premise of the theory, as suggested by the title of the paper, is that plants make a trade-off between allocating carbohydrates for growth or allocating carbohydrates for secondary defense compounds.  Dan Herms subsequently applied the theory in synthesizing the literature on woody ornamentals in his 2002 paper,  “Effects of Fertilization on Insect Resistance of Woody Ornamental Plants: Reassessing an Entrenched Paradigm.” (Environmental Entomology 31(6):923-933.).  I have heard some arborists and others use this paper to argue that we shouldn’t fertilize landscape trees at all.  The problem is they oversimplifying the theory – which is understandable, this is pretty heady stuff.  They get the ‘trade-off’ idea; if plants grow fast they produce lots of yummy stuff for bugs.  But what is often overlooked – even though Herms makes a point to say it – is that when nutrition or other plant resources are low; there is no trade-off.


This figure from Herms and Mattson illustrates the idea.  If nutrients are deficient and we fertilize a plant the plant may increase growth and secondary compounds; it’s not always an either/or situation.  The bottom-line remains the same;  nutrient deficient plants can benefit from fertilization or correcting the factors (e.g., alkaline pH) that made them deficient in the first place.

Koricheva, J. 2002. The Carbon-Nutrient Balance Hypothesis Is Dead; Long Live the Carbon-Nutrient Balance Hypothesis? Oikos 98 (3): 537-539

Proposed phosphate fertilizer ban

Today I received an email alerting members of Washington Friends of Farms and Forests to a proposed ban on phosphate-containing fertilizers in the state of Washington.  Here’s part of the text of the email (I’ve removed underlining, bolding, highlighting etc. so this reads as objectively as possible):

“Concerns with the HB 1271 & SB 5194 banning the sale of fertilizer containing phosphorous:

1) The intent section contains scientifically inaccurate statements, creating a false precedent that turf fertilizer is a significant surface water pollutant and is not necessary for a healthy lawn.

2) It grants the authority to regulate fertilizer sales and use to the Department of Ecology (Currently, the Department of Agriculture regulates fertilizer content and registers it for sale.)

3) It changes the definition of fertilizer used by the Department of Agriculture, creating confusion.

4) It is inconsistent and will be ineffective because it exempts “natural organic sources.” Organic products are high in phosphorous. The ecosystem cannot tell the difference. All fertilizer should be regulated equally.

5) It fails to recognize the expertise of trained lawn care professionals, who should not be prohibited from providing quality service to their customers, including publicly owned golf courses, parks, and sports fields.

6) As written, it bans the use of phosphorous fertilizer for forestry, house plants, shrub beds, golf courses, sports fields and other uses. It is unclear as to private commercial property.

7) It bans the sale of phosphorous fertilizer for flower and vegetable gardens, forestry, house plants, shrub beds, golf courses, sports fields, and many other uses.

8) It bans retailers, including farm stores and ag dealers, from displaying any type of fertilizer containing phosphorous.

9) It fails to address the primary causes of impaired water quality. Regulating something because it’s easy without addressing root causes of the problem accomplishes nothing.”

So, readers and colleagues, do a little homework over the weekend.  Look at the bill itself (both the house and senate bills are the same; the link is for the house bill).  Are these nine concerns valid?  Discuss.