Category: Uncategorized

Are Fertilizer and Insecticide Spikes a Good Idea?

One of the products that I often hear gardeners raving about are their fertilizer / pesticide combination spikes which are supposed to not only feed your plants, but also kill all of the insects which attack them.  I, personally, have not used these products, but I’m generally the kind of person who says “If it works for you then keep using it”.  Still, these spikes bug me a little.  Here’s why.

First of all I should point out that I’m not opposed to fertilizer spikes by themselves.  I’m a little concerned that fertilizer should be spread out instead of concentrated in one place, but still, I don’t consider them that bad.  The insecticides used for these spikes is where I have the problem.  Once upon a time these spikes were made with a chemical called disulfoton (aka disyston) which is bad news.  It’s a water soluble chemical which is highly toxic to people.  If you have an old package of fertilizer / insecticide spikes around there’s a good chance they were made with this chemical.  Do yourself a favor and get rid of them.  This stuff is really toxic and not to be messed with.  On the other hand, if you’ve purchased fertilizer / insecticide spikes recently, then the active insecticide in those spikes is probably imidacloprid.  Imidacloprid is a mixed bag when it comes to safety.  It’s not nealy as toxic as disulfoton, but it’s not non-toxic.  It has been banned in Europe for a variety of reasons, the most important of which seems to be that it was implicated in the collapse of bee hives (imidacloprid is systemic insecticide so it will get into a plants pollen where honey bees could eat it).  At this point it hasn’t been ruled out as having something to do with hive collapse here in the states — though if it does have a role it does not seem to act alone.  It can also affect other beneficial insects who feed on pollen.  Additionally, it has been known to control some pests while allowing mites to go crazy — in fact, it may even increase the rate of mite egg laying.

But imidacloprid is an effective insecticide which works against a wide range of insects which you that you might find on your plants.  It is much safer than many of the older systemic insecticides, and it isn’t readily translocated to fruits (a problem that many people are concerned about with systemic insecticides is the movement of these insecticides into the fruit itself where it can’t be washed off — Imidacloprid is translocated to fruits –just not that much — it moves in the xylem and fruit takes up mostly phloem).

So these spikes are one of those things that I’m wary of.  Not to say you shouldn’t use them, but be aware of what they are and what they could do before you buy them.

Volunteering for duty

One of the advantages of having a couple acres (and not being especially fastidious about weeding) is that sometimes you get your landscape plants for free.  I always keep an eye out for interesting plants that may turn up on their own – or a least get left behind by our bird friends.  Here are some volunteers that have shown up recently at Daisy Hill farm that I’ll work into the landscape.

 


Sassafras (Sassafras albidum) are notoriously difficult to transplant.  I’ll leave these sassafras volunteers where there are and relocate the shrubs in the bed.  I’m looking forward to some awesome fall color in a few years.

 


The native range of redbud (Cercis canadensis) only extends into the southernmost counties of Michigan but they generally do fine here in the Lansing area (just north of the end of the native range).   We have an old redbud in the front of our house so we get volunteers from time to time.  This one is on the edge of our patio so it’s easy to keep an eye on.  I’ll let it grow on another year or so and then find it home.

 


Most people probably wouldn’t get too excited about eastern redcedars (Juniperus virginiana) showing up on their own.   When I was with the US Forest Service, my grad student and I did research on seed germination of eastern redcedar and Rocky mountain juniper (J. scopulorum).  Ironically they can be difficult to grow as seedlings in nurseries because the seed are doubly dormant (they have a tough seed coat that requires scarification and the embryo is dormant and requires cold stratification).  I’m planting conifers as a screen on the south side of property. I’ll move these guys and a couple of their friends in the spring.

Further decline of “public” education

“The Texas A&M University System is moving ahead with a controversial method of evaluating how much professors are worth, based on their salaries, how much research money they bring in, and how much money they generate from teaching, The Bryan-College Station Eagle reports. Under the proposal, officials will add the money generated by each professor and subtract that amount from his or her salary to get a bottom-line value for each, according to the article.”

This bodes ill for faculty like myself who have Extension appointments.  For those of you who aren’t familiar with how Extension works, Extension specialists educate citizens outside university classrooms.  But with declining state support for universities, their administrators in turn focus on income generation from grants and tuition.  Extension specialists do get grants, but for those of us in areas outside food and fiber research (which is what the USDA funds), there’s not much money available.

Bottom line?  According to this model I’m not just worth nothing – I’m worth less than nothing.  I’m not worried about my job (I have tenure after all), but for the direction that outreach education is heading.  What will happen is that Extension specialists will be pushed back into classroom teaching, leaving no time for educating the rest of the state citizens.  Outreach education will become little more than an afterthought.

The ironic thing about this trend is that Extension is one of the biggest bargains states get from their land grant universities.  Extension education includes Master Gardeners as well as other programs tailored to local state and county needs.

It’s sad that Texas A&M puts so little value on outreach education.  What’s even sadder is that this economic approach will undoubtedly be adopted by other state universities.

Rubber mulch – the discussion continues

Almost a year ago I posted my complaints about rubber mulch (you can find the posting here).  This week I was contacted by Jesse, a purveyor of rubber mulches.  We’ve had a very civil discussion about the topic, and he asked me to review his fact sheet.

Which leads me to today’s assignment. I have no personal experience with rubber mulch, so I’d like to hear from you about your experiences with this product.  Specifically:

1) Have you seen fungi growing on rubber mulch?

2) Have you had issues with the heat captured by the product – either to your feet or to your plants?

3) Does the mulch continue to smell, especially when hot?

4) How quickly do you notice degradation of the product?

Obviously this is anecdotal, not scientific, evidence.  But the scientific literature regarding rubber mulch is thin, and anecdotal evidence can often indicate directions that science should explore.  Perhaps this can be the beginning of such a study.

Confessions of a carbon sequestration skeptic

One of the potential environmental benefits that came up in our discussion of the pro’s and con’s of turfgrass was carbon sequestration.  The basic premise of carbon sequestration is to take CO2 out of the atmosphere and ‘lock it up’ in a form that won’t contribute to further global warming.  One of the fallacies floating around these days is that any plant that photosynthesizes, takes up CO2 and thereby sequesters carbon.  What we need to realize is that leaves give off CO2 at night via respiration and all non-photosynthetic (non-green) plant parts such as roots and stems give off CO2 virtually all the time.  Turfgrass has some potential to sequester carbon, primarily as soil C. If we consider that a 7” deep layer of soil weighs 2 million pounds, increasing soil carbon by 1% can sequester 20,000 lbs of C per acre.  How long does it take turfgrass to increase soil C by 1%?  Don’t know, but I’m sure it takes awhile.  Also, there is a limit to amount of carbon a give soil can store as C is respired away by microbial activity so eventually a steady state will be reached.  (Plus we haven’t even subtracted out fossil fuel carbon to maintain turf).  Some plants, such as trees, do have the capacity to sequester carbon in wood for long periods – think redwoods, sequoias and redcedars.  But these trees cover only a small fraction of the world land area.  Intensively managed forestry plantations can take large amounts of carbon out of the atmosphere and sequester it into wood.  The question then becomes what do you do with the wood?  If we burn it for biomass energy; Foof! All that C is right back in the atmosphere.  Still better than burning fossil fuels but also a little less than carbon neutral at best.  We can build houses with the wood from the plantation – the carbon will be sequestered as long as the house lasts.  My home and barn were built in the 1890’s so the carbon taken out of the atmosphere by those trees is still locked up.  If we really want to get serious about carbon sequestration, however, our best strategy would be to convert the entire Upper Peninsula of Michigan to fast growing poplar plantations, harvest the wood every 15 years, and sink the logs in Lake Superior where the cold water will prevent decay.  Sound funny?  I’m not the only person thinking this way.  See Strand and Bedford 2009. Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments Environ. Sci. Technol., 2009, 43 (4), pp 1000–1007. http://pubs.acs.org/doi/abs/10.1021/es8015556  

 

Bottom line: carbon sequestration is a very complex process and sequestering carbon for more than a few decades takes more creativity and brain-power than most of us can muster.  However, trees and landscape plants do have important role to play in mitigating climate change and it doesn’t require heroic feats of engineering.  Trees and landscape plants can effectively cool buildings, thereby reducing air conditioner use and save fossil fuels – see the USDA Forest Service Urban Forestry Research site for a few examples http://www.fs.fed.us/psw/programs/cufr/research/studies.php?TopicID=3   ultimately this is landscape horticulture’s contribution to climate change.  Carbon sequestration?  It’s a drop in a very big bucket.

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Dog Spots

There is a general misunderstanding among the gardening (and yard owning) community about dog spots.  It seems that some people believe that dog spots occur because of a high or low pH or because of some sort of poison in a dog’s urine, but that really isn’t the case at all.  Dog spots occur because of something that I pointed out a few weeks ago in another post.  Urine contains a lot of nitrogen.  When a dog pees on your lawn that extra nitrogen isn’t used and so ends up being poisonous to the grass which is peed upon.  You’ll notice that around the periphery of a dog spot the grass is particularly bright green.  This is because the extra nitrogen helps the grass in that location rather than poisoning it.  If you want to get rid of a dog spot the best thing to do is to follow your dog around carrying a five gallon bucket of water and pour it over the spot as soon as the dog pees — this should stop the grass from dying, but will probably not get rid of all the extra nitrogen and so you’ll end up with a bright green spot instead of a brown one.

Is brown the new green?

An acquaintance of mine (not coincidentally, an irrigation supplier) brought to my attention a recent editorial from USA today by Laura Vanderkam, entitled ‘’Out of Fashion: Green Lawns.” http://www.usatoday.com/news/opinion/forum/2010-08-17-column17_ST_N.htm?loc=interstitialskip#uslPageReturn  The basic premise of the editorial is that we Americans are ruining the environment by maintaining lawns.  Now, to be sure, there is plenty of room for improvement in lawn and landscape maintenance, particularly in terms of water management and pesticide use.  But, for better or worse, Americans love their lawns.  I love my lawn, imperfect though it may be.  We’ve got a couple of big oaks in the backyard and I love to lay a blanket in the shade and read a magazine on Sunday afternoon or just doze with the Tigers game on in the background.  Love to play croquet and bocce.  Love to kick a soccer ball around with my daughter.  In the interest of full disclosure, my lawn will not win any awards.  At this moment about 75% of my lawn is brown, panting in the heat of our first true summer in several years.  I water a small portion of the lawn for the aforementioned croquet/bocce playing, and magazine reading/ Tigers’ game snoozing.  For most part, however, I take a lazzez faire attitude to lawn upkeep; I keep a 3” mower height, apply a little bit of Weed-b-Gone every other year in the section nearest the house when the dandelions are ready to drive me to distraction and, if I remember, put down a half rate of fertilizer in the spring.  Nevertheless I was taken aback by Ms. Vanderkam’s assertion, “Few parents would light a cigarette at a playground anymore, even if it’s not illegal, and we should start treating the presence of a vast, green, cropped grass lawn in the middle of summer the same way: as a weird and antisocial thing.”


Let the games begin. Mrs. Cregg scores again on the opening day of Cornhole season 2010.

Wierd and antisocial? Really. From May to September, our lawn is the most social part of our place.  What’s really needed, and often the hardest to find, is some middle ground.  It’s easy to resent people that belong to homeowners associations that require perfect lawns and hire ‘Chemicals R Us’ to maintain their pristine turf.  However, lawns and landscapes can provide an array of benefits, some tangible like oxygen produciton and cooler air temperature; and some less tangible, like a perfect croquet shot..  We can, and should, look to reduce water and chemical use on lawns.  But Ms. Vanderkam will get me off my John Deere riding mower when she can pry the steering wheel from my cold, dead fingers.

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Balanced Fertilizer and Peak Phosphorus

When I first started reading extension recommendations for plants around 15 years ago now, I read a lot about “balanced fertilizers”.  Today I still see balanced fertilizers recommended, but not nearly as frequently, which is a good thing.

At this point you may be asking yourself “what is a balanced fertilizer?”  A balanced fertilizer is one that has three numbers on its label which are the same — such as a 10-10-10 or a 14-14-14 (Nitrogen, Phosphorus and Potassium are the three nutrients indicated by
these numbers).  Although it might seem like equal numbers would mean equal amounts of these nutrients, these numbers actually indicate percent Nitrogen, percent P expressed as P2O5 (in other words, if you took all of the phosphorus present in the fertilizer, made it into P2O5 and then added it back to the fertilizer and figured out what percent of the fertilizer that made up — that would be the second number) and percent potassium expressed as K2O (basically the same as the phosphorus example you saw previously).

But here’s the problem.  The amount of phosphorus, and often potassium, that is added when you use a balanced fertilizer is typically out of line with the amount that the plant needs.  This is because fertilizers are usually applied based on the amount of nitrogen that a plant needs.  The reason that a balanced fertilizer was usually recommended was that phosphorus and potassium levels in these fertilizers is high enough that they provide all of those elements that a plant needed without being toxic to the plant.  The problem is that, while the levels of these nutrients added might not be toxic, they are in excess of what is usually needed.

OK, so we’re adding excess phosphorus and potassium, what’s the problem?  Well, for the potassium the problem isn’t usually that big a deal.  In fact, a fertilizer bag with the first and third numbers equal may be what’s called for in many cases — fruits and nuts in particular often like a higher level of potassium.  Additionally, the world has a pretty big store of potassium so we’re not likely to run out any time soon.  Phosphorus, on the other hand, is a little bit different.

Phosphorus is a bit more hard to find in large quantity than either of the other elements in a bag of fertilizer.  Because of this it is often the element that limits the growth of plants, for example algae.  When phosphorus runs off into a lake or other body of water it can allow algae to go crazy and use up all of the oxygen in the water killing fish and other creatures (actually it’s the dead algae that do this — bacteria use oxygen while breaking the algae down).  Most of you are familiar with this and know that it’s the reason why Minnesota and now Wisconsin have banned the use of phosphorus fertilizers on lawns without a soil test.

But here’s what you may not know.  Most of the phosphorus which we use for fertilizers comes from rock phosphate.  Rock phosphate is mined in only a few places around the world, Florida being one.  Just as it is a foregone conclusion that we will run out of oil someday, it is also a foregone, but lesser known, conclusion that we will run out of rock phosphate.  Estimates are that we will reach “Peak Phosphorus” (in other words maximum phosphorus production.) in 20 years or so and that we will run out in 50 – 100 years.  Here’s an interesting article on the situation  http://www.foreignpolicy.com/articles/2010/04/20/peak_phosphorus

So conserve our natural resources and skip the balanced fertilizer.  When asked for a general use fertilizer recommendation I usually recommend something with a ratio of roughly 5-1-2, with a higher potassium content if you’re growing fruits or nuts.

Restoration ecologists – you need us! Part 2.

Last month Linda posted on the need for horticultural knowledge for those trying to restore native habitats or at least establish native plants. There seems to be a pervasive notion that if we plant natives all we have to do is stick them in the ground and walk away. They’re native, right?  Don’t need irrigation; don’t need fertilizer; all that good jazz.   Well, often there is lot more to it than that.

 


A case in point.  Over the past couple of years I’ve been watching an unintended experiment near the State Capitol grounds in Olympia, WA.   The State opened up a vista so that the south end of Puget Sound and the Olympic Mountains were visible from the Capitol campus. It’s a lovely view.   As part of the development, a switchback trail was established on the steep hillside to connect the Capitol grounds with the park surrounding Capitol Lake below. A great idea.  Along the trial the hillside was planted with an array of native plants such as Oregon grape, salal, alder, and western redcedar.  Another fine idea.  Now comes the problem.  Near as I can tell, there was no plan for maintaining these native plants.  In fairly short order the hillside has become overrun with grasses, dandelions, and Himalayan blackberries – not exactly the desired effect.  And therein lies the rub.  Everyone is on board to plant natives but who’s on board for the hard work to maintain them.  Keeping weedy species from this planting by hand would take an army volunteers.  Burning is likely out due to the proximity of the Capitol and probably wouldn’t promote the desired species.  The answer?  Most likely a combination of hand-weeding and herbicides.  It is interesting that when the end justifies the means, herbicide is not such a dirty word anymore.  So there you go.   In order to effectively establish and maintain native plants, not only do we need to know about Mahonia aquifolium, Gaultheria shallon, and Alnus rubra; but it also helps to know about glyphosate, flumioxazin, and triclopyr.

The importance of knowing your plants

One of the first courses a horticulture student takes is plant materials, or, in the case of a forestry student, dendrology.  Why?  Pretty simple; it’s hard to select plants if you don’t know what they are and what they’ll do in the landscape. Of course, the classic example is a large tree or shrub planted in a tight spot that eventually devours an entire house.  But we usually don’t have to look too far to find situations where a homeowner or landscaper clearly had no idea what plant he or she was dealing with.  To wit, a couple of recent examples of poor plant choices (maybe this can be our next series after “Why do nurseries still grow THAT?”)

I spotted the first example wandering through downtown in my hometown of Olympia, WA.  At first glace it looks like an ordinary hedge; boxy to by sure, but nothing remarkable.

As I passed by though I noticed the hedge was actually a weeping Norway spruce (Picea abies ‘pendula’ – actually it could have been an ‘inversa’ – the repeated butchering made it hard to tell).  Either way, what could have otherwise been a fairly interesting plant had been reduced to a squared-off blob of blech.  The other side, of course, is that if a squared off blob of blech is truly desired there are cheaper and easier ways to achieve the effect.

The other example of the perils of not knowing your plant material comes from northern Michigan.   This case represents that other extreme of trees that grow too large for their space.  Here the homeowner wanted to screen his house (on the left but out of camera range to protect the guilty!) from the railroad track on the right of the photo.  Solution: Plant some conifers! Sounds like a good idea to me.

Only problem – the owner chose to plant the screen with dwarf Alberta spruces!  As with the blob of blech, the property owner could have achieved the desired screen in a couple of years and at a small fraction of the cost with seedlings from their local conservation district or seedling nursery.  In any event, we’ll check back in about 40 years and see how it’s working out for them…