Questions on sustainability

Linda’s recent post on the sustainability of topiaries got me to thinking, is any horticultural practice sustainable?  And, does it matter?


Picking up on the topiary theme I thought of the ultimate form of tree manipulation, bonsai.  I few years ago I visited the National Arboretum in Washington DC, which includes an incredible bonsai display.  Some of the bonsai specimens in the collection originated in Japan and are over 300 years old.  Is 300 years long enough to consider this a sustainable practice?  Does it matter as long as there are individuals willing to devote the time and effort to tend and prune these awesome and inspiring plants?


More recently I visited the International Rose Garden at Washington Park in Portland.  Established over 90 years ago the garden is one of the premier attractions in Washington Park and in Portland.  Maintaining the garden, however, requires paid staff and an army of volunteers.  Is 90 years long enough to consider this sustainable?  Does it matter as long as the city is willing to commit resources and volunteers are willing to line up to dead-head and pull weeds?


Closer to home, I maintain about an acre of my place in lawn and various beds – trees, shrubs, herbaceous perennials and even a few (gasp) annuals.  Is this sustainable?  Does it matter as along as my family and I enjoy our surroundings and are willing to commit the time and effort to mow, weed, edge, prune and dead-head?

Clematis mystery solved

Friday’s quiz was a tough one. Bernadette and Lisa B. gave it a good shot, guessing that this might be a phosphorus deficiency. While they’re on the right track (it is a nutritional disorder), the mineral of interest is iron, and it’s a toxicity problem, not a deficiency.

Under wet conditions (the affected Clematis is in the part of our landscape with a perched water table – see the March 15 posting), iron is predominantly in the Fe+2 form (ferrous) rather than the Fe+3 form (ferric). The ferrous form is easily taken up by roots, and when leaves accumulate too much iron they turn reddish-brown.  This diagnostic characteristic is called bronzing, and it’s different than the reddening caused by anthocyanin accumulation.  (As an aside, nonagricultural landscapes rarely have phosphorus deficiencies and are more likely to contain excessive levels of phosphorus.)

Finally, all this talk of iron has reminded me of one of my favorite chemistry puzzles – see if you can figure out what this is:

Give up?  It’s a ferrous wheel!

Friday quiz – a tale of two clematis

These two Clematis are the same cultivar growing in my landscape about 15 feet apart. Both are growing on a fence facing north. Compare the leaves of the two:

Normal, happy Clematis

Not-so-happy or -normal Clematis

What do you think is causing the leaf discoloration? Very large hint: this is not a biotic stressor. Another hint: you’ve seen this part of our landscape before…back in March. For full credit, identify both direct and indirect environmental stress (in other words, [1] what is directly causing the discoloration in the leaves, and what is allowing [1] to occur, thereby causing stress indirectly)?

Answers on Monday – have a happy 4th of July.!

Organic farming study at – gasp! – a research university

There is a common misperception among some that university researchers are in the pocket of Big Ag (see June 11 and 13 posts). So here’s a link to an article in today’s Seattle Times about the benefits of organic farming from a study at Washington State University.  The research was published in Nature (one of the most revered of the scientific journals).