The potential for the Canadian Nursery
Landscape Association’s “Canadian Certified Horticultural Technician”
programme is great, but how good is the present model?
Two true stories prompted
this particular topic.
First, a good friend and past president of the Rhododendron Society of
Canada, wrote on June 27th: “This young man by the name of Joe, bought six
rhodos and was looking for advice on how best to plant them. He read ARS
info on the Web and went to (a large west-end Toronto garden centre) for
peat moss and more advice. He was told by some lady (he got the impression
that she may be the owner) that rhodies are too difficult to grow and he
should take them back.
“Now, how do you like that?
“Fortunately Joe found out that there are public plantings of rhododendrons
and he felt that if they can grow in the parks, surely he can make them grow
in his garden. He came to my garden yesterday and after seeing my collection
of over 150 plants in the back, he was convinced that they are wonderful and
easy plants to take care of, if planted properly and in the right location.”
Second, listener Erna Letson of St. Agatha Ontario wrote several weeks ago
about caterpillars on her copper beech tree. I replied, in one of my
articles that not knowing exactly which caterpillar it was made it difficult
to advise just what to use. I did basically suggest Bacillus thuringiensis
that is a ‘natural’ control used for many, many caterpillars.
She has since responded, saying (excerpted): “I described the worm to [a
gentleman at the University of Guelph Arboretum] and he was able to respond
within days [with] the possible ID.”
She went on, “A close look at this minute caterpillar and watching it
spinning a web was enough to identify it as a fall web worm. I called a
garden centre and was told that the solution was to spray a product called
Ambush, (Permethrin). My only concern is, that the tree is 22 yrs old and
approx. 35 ft. tall and how could my husband or I possibly do this topical
spray safely. I hate to use any insecticides and I wonder if there is a
safer way to tackle the problem.”
I advised Erna that the gentleman at the University of Guelph may have been
wrong. That early in the spring, I would think the caterpillar was more
likely a tent, rather than a fall web-worm. The two make similar though not
exactly the same ‘tents’. I believe, as I indicated originally, the insect
could well be the tent caterpillar. The telling feature of its tents are the
way they are built around the branch crotches of the tree(s) rather than
around the foliage as is the case with the (generally) later fall webworm.
More importantly, I was concerned about the recommendation she received from
“the garden centre” about just what to spray. Ambush, though still available
in some garden centres, is no longer a registered product for domestic
use in Canada. It was the older form of permethrin that has now been
supplanted by the newer and much less toxic water-based permethrin (i.e.
Doktor Doom Yellow Label is 50% permethrin). Obviously it’s the latter that
should have been recommended, especially since Erna expressly said she
didn’t wish to use strong insecticides! “How-ever,” I wrote, “I go back to
my original recommendation of Bacillus thuringiensis. It is the
recognized answer for caterpillars--especially those of the eastern tent
These are just two samples of errors in advice I hear about at least weekly.
As far back as April and again in May 1999, I wrote recommending that
gardeners looking for the best advice at a garden centre should search out
managers or staff that had there “CCHT” designation. As this audience will
know, that stands for Canadian Certified Horticultural Technician programme.
However, this July I had occasion to read through two major documents
relating to that programme. The Training Manual (Retail Garden Centre
Professional), for example, is 127 pages (8˝ x 11”) but totally in black and
white. In reference to insects there are only verbal descriptions;
photographs would have been oh so much better. In the case of weeds, there
are nine black and white sketches, but they too leave much to be desired.
However, over a dozen other common weeds listed are not illustrated at all!
Many other shortcomings are obvious. For example, the hardiness map used is
that of the U.S.D.A. rather than the Canadian Plant Hardiness Zone Map (I
still think the 1967 version is the one that should be being used!). There
is, however, a chart that attempts to compare the zones of the two maps--a
task that is not at all easy, if possible at all. The explanation of the two
hardiness maps (on page 5 of the Manual) does not jive with what actually
appears in Appendix 1 of the publication, and the explanation of zones
having to do with “The minimum winter temperatures that woody and herbaceous
plants have demonstrated ongoing survival in the landscape….” is not only
lacking, but definitely incorrect, at least when it comes to the Canadian
Botanical names are never italicized, as they should be, although cultivar
names are shown in single quotes correctly. Oddly enough no mention is made
of the newer trademarked names that are soon going to dominate.
As mentioned in one of my opening stories, I have a long-standing concern
about pesticide recommendations. On page 49 of the Training Manual they
actually suggest only “pet-proof traps baited with metaldehyde” as a
solution for slugs. No mention is made of diatomaceous earth or the newer
Ferric phosphate product from Safer’s.
I also noted ever so many typos, spelling errors and exclusions. For
example, that super aggressive perennial, goutweed (Aegopodium podagraria
‘Variegatum’), is listed as “Aegopodium podograria”--that’s right
with incorrect spelling of the species, and no mention of the variegated
form although under ‘Features’ they say “variegated white and green leaves”.
I guess they didn’t realize there is a solid green form as well. However, I
think there should have been more than just the two words “vigorous,
aggressive” in the ‘Features’ write-up. Customers in garden centres should
likely be told that if they sell this to a new gardener they could well face
a highly distressed and angry customer two years or so later! And, they
might also have informed: 1) that the plant should be planted in a
container, even if in the ground, and 2) that it cannot be killed with
either selective (2-4-D/Mecoprop/Dicamba) or non-selective (Roundup) types.
One of the funniest spelling errors is the insect listed as “Bruce Spanworm”
which to me indicates rather poor proofreading. Just what the source of some
of the information in the Training Manual was, is open to conjecture. But,
since one of the spelling errors in “podagraria” is the same as in
the Sheridan Nurseries Garden Guide, perhaps we have a clue!
On the other hand, Chris Andrews, CNLA executive director, told me they were
working hand in hand with “the Americans” so possibly that explains some of
the problems, including the over-use of the USDA hardiness map.
In thinking about improvements for this programme it seems to me that it
should be entirely Web-based. There are already mentions in the Training
Manual of checking the CNLA’s CD-ROM of plants, so why not continue in that
direction? Coincidentally I recently checked the Web and found the
University of Georgia’s site (http://aged.ces.uga.edu/)
where they have exams on a huge range of topics including National Nursery
Landscape Plants and National Nursery Landscape Disorders. Just compare
their colour photos with the text or poor black and white sketches of the
Chris Andrews, executive director of CNLA, suggested he would get his
education and marketing coordinator, Rachel Corbeil, to call me about the
CCHT programme since it was her area. Rachel did that and told me she was
unaware of the errors and omissions I mentioned to her. She also said the
latest revision of the Retail Garden Centre Professional manual was in the
process of being developed and that she expected to see some proofs within a
month. She also said that they hope, eventually, to sell the manual to the
U.S. just as they currently buy the landscape maintenance ones from the
Associated Landscape Con-tractors of America.
That one point may well mean boosting the prominence of the U.S.D.A.
hardiness map, rather than reducing it in favour of our own Canadian map. I
hope that will not be the case! There should be a way of having two
editions, one for Canada featuring only the Canadian map, and one for the
US, using the U.S.D.A. map.
In preparing for this article, I did contact a number of “sea-soned” garden
centre employees in several provinces who have “taken the course” and found
a consensus that it could indeed be much, much better. To sum up, the CCHT
programme is new, it is a good start, it’s being constantly refined, and
according to Chris Andrews, Rachel is looking at putting it on the Web.
Hopefully many of the gross errors will be corrected in the next version!
And, it seems to me they are years behind the times by not being on the Web