Jeff Gillman's Hort Research that Gardeners can Use

The latest by Jeff Gillman, associate professor of horticulture at the University of Minnesota.  We thank him for his quarterly reports to us, which are all compiled right here.   

I went to graduate school with an interesting guy named Bill Klingeman. He was one of my favorite people to discuss research with because he always saw things differently than I did, something that I think we both benefitted from.  Over the last ten years or so I’ve fallen out of touch with Bill besides the odd phone call or e-mail, but recently I had the opportunity to read an article that he wrote which I think you’ll enjoy hearing about. 

Back when we were in school Bill was interested in how people perceived the damage inflicted on plants by insects.  In other words, how damaged does a plant need to be before people notice or care.   

What Landscape Managers Think and Know about Lower-Care Plants

Bill's most recent article is related - this time he asked lawn care and landscape management companies about their willingness to recommend insect- and disease-resistant plants (assuming, perhaps, that they wouldn’t be likely to because it might mean fewer jobs).  But most of the respondents said they were willing to recommend the resistant plants.  Also, they believed that the availability of resistant ornamental plants would help, not hurt, their business.  In fact, only about 4% of respondents thought that the availability of more care-free plants might hurt their business.  When asked about natives and their resistance to pests, about 59% of land managers felt that ornamental native plants were at least slightly more resistant to pests than nonnatives.

Besides asking them about their willingness to use pest-resistant plants, Bill also tested their knowledge by asking respondents about the resistance of particular plants to particular insects and diseases.  More years of experience generally resulted in better performance at the test, but more education did not!  Having more customers was, likewise, not a good way to predict their level of knowledge.  Here’s the part that I find interesting: “Respondents with the least knowledge about insect- and disease-resistant ornamental plants were more likely than knowledgeable peers to expect a greater need for site visits to client landscapes.”  In other words, if they don’t know much, they’ll come by more often.¹

So, what does this mean for you?  Simple, find yourself a landscape professional with as many years of experience as possible (within reason of course!)  And now, on to the other studies…

The Sun Kills Weeds! 
Solarization is a method of ridding an area of plant life by placing plastic over the area that you want cleared and allowing the sun to do its work - but which plastic works best?  The answer: Poly Pak, ISO, and VeriPack.  Other plastic covers worked also, but the durability of these three covers tended to be better.²

Controlling Bird's Nest Fungi  
If you have "bird’s nest" fungi growing in your mulch (it's easy to identify because it actually looks like a little bird's nest - complete with a few eggs!) then you might consider using recycled mushroom compost.  Using 40% or more of this compost mixed with your regular mulch should help to suppress this common type of fungus and others, too!³

Just for Susan - Fescues!

Lots of research time is spent comparing different varieties of various crops with each other.  Recently an article on fescues (a type of grass in many lawns) was published which revealed the best of these grasses for conditions where extra irrigation and fertilizer, besides that which Mother Nature offers, wouldn't be forthcoming.  Those cultivars included Intrigue, Columbra, Sandpiper, and Reliant II.⁴

African Violets and Hand Cream

If you’re considering brushing your African violets with your lotion-covered hand, think again!  Brushing these plants for 30-90 seconds three times with a bare hand-lotion treated hand can stunt their growth.  So at this point you may be asking yourself why anyone would pet their African violet, right?  In the words of the authors, "Because of their brightly colored flowers and often hairy leaves, people are attracted to African violets and often want to touch the leaves and flowers."⁵

Bulb Biters 

Voles are well known connoisseurs of the bulbs you plant in your garden, but which bulbs are most likely to get chomped?  Researchers at Cornell fed bulbs to voles to find out.  Tulips were the only bulb with no resistance to voles, but hyacinth, crocus, corn leaf iris, dutch and dwarf iris, onion and squill weren't much better.

Showing better resistance to voles were painted arum, camass, glory-of-the-snow, autumn crocus, crown imperial, Persian fritillaria, snowdrop, and grape hyacinth; showing the most resistance as a group were paperwhites and daffodils.  The authors of this paper also reported that autumn crocus may have killed seven voles in the study.⁶

Bird's nest fungi photo by Adam Rice.  African violet photo by LumaChrome.  Study citations below the jump.

¹ Klingeman, W. E., G. V. Pettis, and S. K. Braman.  2009.  Lawn care and landscape maintenance professional acceptance of insect- and disease-resistant ornamental plants.  HortScience 44(6): 1608-1615.

²Gill, H. K., R. McSorley, and D. D. Treadwell.  2009.  Comparative Performance of Different Plastic Films for Soil Solarization and Weed Suppression.  HortTechnology 19: 769-774.

³Fidanza, M. A., and D. D. Davis.  2009.  Recycled mushroom compost suppresses bird’s nest fungi in landscape mulch.  Journal of Environmental Horticulture 27(4):238-240.

⁴Bertin, C. A. F. Senesac, F. S. Rossi, A. DiTommaso and L. A. Weston.  2009.  Evaluation of Selected Fine-leaf Fescue Cultivars for Their Turfgrass Quality and Weed Suppressive Ability in Field Settings.  HortTechnology 19: 660-668.

⁵Brotton, J. C., and J. C. Cole.  2009.  Brushing Using a Hand Coated with Body Lotion or in a Latex Glove Decreases African Violet Plant Quality and Size.  HortTechnology 19: 613-616.

⁶Curtis, P.D., G.B. Curtis, and W. B. Miller.  2009.  relative resistancne of ornamental flowering bulbs to feeding damage by voles.  HortTechnology 19: 499-503.

Comments

[Joseph Tychonievich]

colchicum KILLED 7 voles in the study? Awesome... I'm going to have to plant some.

[Cheryl]

why "control" Birds Next Fungi? I think its cute and it isn't hurting the plant, right?

[Bob]

Why would one want to suppress "Birds Nest Fungus"? Fascinating stuff...it's always worth a look!

I wish I had more varieties of woodland mushroom in the yard; their colors, and intricacies of their structures, are amazing!

[Jeff Gillman]

Good point on the birds nest fungi --- BUT --- It also helps control artillery fungi which you might not like as much.

[Michelle]

I, too, would like to know why I would want to kill bird's nest fungus. Thanks, and also thanks for identifying my mystery fungus!

[Kathy J, Washington Gardener Mag]

I pet my African Violets frequently - mostly to remove the accumulated cat hair. Will keep in mind not to do so after lotioning up.

[Elizabeth Stump]

Don't let the PETA folk know about the bulb study. Last thing you need also is animal rights activists attacking... plant researchers.

Interesting study using mushroom compost to suppress other fungi. Hmmm, first hypothesis that comes to mind (without reading the study yet) is that the compost, already inoculated with almost an anti-body like dose of mushroom fungi, prohibits growth, much like a vaccination of dead or weakened viruses/diseases can immunize you from a disease. I will have to read to see if this thought bears any likeness to the results of the study.