Veggie garden safety

A few months ago I posted a caution about using old pressure-treated timbers for vegetable gardens (see my Sept. 23 posting).  I now routinely get questions about alternatives to these arsenic-laden materials, especially new treated lumber.  What’s in the new wood that makes it rot resistant, and is it dangerous?

Rather than arsenic, new pressure-treated lumber has copper as its active ingredient.  Though it also will leach out of the wood, there is not a human health hazard associated with its uptake by plants or animals. … Continue reading this article “Veggie garden safety”

Growing a greener Christmas tree

Among the many hats I wear, one of the most enjoyable is that of an Extension Specialist working with Christmas tree growers here in Michigan and surrounding states.  I suppose part of the satisfaction stems from the fact that my first real job was shearing Christmas trees in southwest Washington during my high school summers.  To give you an idea how long ago this was, the minimum wage when I started the summer between my sophomore and junior years was $2.20 per hour.… Continue reading this article “Growing a greener Christmas tree”

Friday puzzle solved!

Great discussion over the weekend, with some very astute observations.  If you looked at the brown needles under the tree in Friday’s picture, you may have noticed that some of them weren’t needles:

Not only was this tree planted too deeply, as several of you pointed out, but the burlap and twine were left intact.  It appears the nylon twine has already started to girdle the trunk, based on the trunk swelling just above where the twine is wrapped.… Continue reading this article “Friday puzzle solved!”

Friday fun!

It’s the holidays, but this pine tree is feeling anything but merry.  It was installed about a year ago.  While the upper foliage looks lush and green, the lower branches have no new needles and in fact the current needles are dropping:

This is a two part question:

1)  What might be directly responsible for the needle decline on the lower branches?  (Hint:  this is caused by the plant itself.)

2)  What might be the underlying stress causing the needle decline? … Continue reading this article “Friday fun!”

Let It Snow!

Here in Minnesota one of the things that we need to worry about is the cold.  Over the winter we can see temperatures down into the -30s (even the -40s in the Northern part of the state) and it can damage many of the plants that we grow.  The tops of the trees are usually able to handle these types of temperatures — though a good heavy snowfall can cause a limb to collapse now and again.… Continue reading this article “Let It Snow!”

Inspecting nursery plants, part IV

(Note:  this is a really LONG post.  Not in text – but in photos!  Sorry for all the scrolling.)

I don’t know about you, but after spending three weeks on my hands and knees looking for trunk rots, surface roots, and suckers, I’m ready to become bipedal again.  So today let’s look at trunks – and what shouldn’t be missing on them.

Many young trees have numerous short branches along their trunk, as shown in the photo below:

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Unfortunately, many nurseries and gardeners think this looks scruffy, and respond by pruning these branches off, leaving a tree such as the one in this picture:

Personally, I think these trees look like lollipops, but aesthetics aside, this type of pruning can inadvertently damage young trees. … Continue reading this article “Inspecting nursery plants, part IV”

I think about these things as I peer into my coffee cup…

This winter, we’re working on renovating part of the campus Hort Garden. We’re tossing around lots of ideas/themes, but I’m leaning towards a garden full of “Plants with a Purpose”. Edible, fiber-producing, medicinal…you get my drift.  Which brings me to today’s bloggerific topic: beverages.

Mankind has, throughout history, infused or fermented just about every species of flora in an effort to get either perked up or calmed down.  These plant potions are often classified anthropologically as, ahem, “ceremonial beverages”.… Continue reading this article “I think about these things as I peer into my coffee cup…”

Salt solutions

Hopefully everyone got their filling of turkey and dressing over the long Thanksgiving weekend.  I used our unusually mild weather on Saturday to celebrate a time-honored tradition around the Cregg farm: The annual cursing of the tangled Christmas lights.

Turning the calendar over to December in Michigan means another Midwest tradition is just around the corner as well: The annual dumping of the road salt.  Although totals vary, at least one source estimates that road crews pour 8 million tons of salt on roads in the US each year. … Continue reading this article “Salt solutions”

Friday puzzle answers!

Good speculation on the rhododendron leaf damage!  Jim in Wisconsin zoomed right in on the causes:  the first photo was taken on a year where we had an unseasonable freeze right as leaves were expanding, and the second was taken on a year where we had unseasonably hot weather as leaves were expanding.

In both cases, the ultimate cause of damage is lack of water in rapidly expanding tissues.  Once dormancy is broken, leaf and flower buds are highly sensitive to environmental extremes – they are expanding and are most sensitive to anything that interferes with water content.… Continue reading this article “Friday puzzle answers!”

Justice finally

This just in from our Saturday paper:  US man wanted for ecoterror sentenced in China.

For those of you who don’t know my history, I was an associate professor at the Center for Urban Horticulture at UW when it was firebombed in May 2001 by ecoterrorists.  It’s a long and sad story, but if there’s an upside, it’s that this event was the ultimate reason I’m doing what I’m doing now.  Otherwise I would probably still be doing lab-based research – which is good and necessary, but not nearly as personally satisfying as working directly with people who want to understand and apply plant sciences as they relate to garden and landscape sustainability.… Continue reading this article “Justice finally”