plant regulation

Jane McGary
Tue, 28 Jul 2009 11:03:44 PDT
Boyce Tankersley wrote,
For a less than 1% return on investment, we (the USA) are going to
>disrupt a major industry (yes, ornamental horticulture brings in more
>revenue than corn and soybeans combined in Illinois) that has a very low
>level of success?

I can add that ornamental horticulture produces more revenue in the 
state of Oregon than any other agricultural industry, including cattle raising.

>Why is there so much pressure to ascribe blame to the ornamental
>horticulture industry who will never be in a position to establish
>plants next to or in natural areas by the millions without government
>support? It appears to be a feel good effort (do something, even if some
>facts annoyingly don't support the action).

The answer is probably that the farm industry lobbies intensively and 
has plenty of legislators in its pockets, while the nursery industry 
doesn't. Farm subsidies are well known as a "third rail" of American 
politics, but I don't think there are any price supports for growing 
rhododendrons. (There is a significant tax advantage, however, for 
growing Christmas trees -- one reason the land around where I live is 
covered with them.)

I've been growing several thousand plant species for 25 years in a 
habitat where invasion might be expected to occur: degraded farmland, 
formerly Douglas fir forest, abutting Christmas tree farms (which are 
treated regularly with herbicide and cultivation) and overgrazed 
pasture. There were a great many introduced weeds present when I came 
here, some of which (e.g., Scotch broom) I've been able to control on 
my own property, and others (Himalayan blackberry [purposely 
introduced by farmers], hawkweed [came in with imported fodder]) that 
are ineradicable. I don't think I have ever seen a garden species 
appear in UNDISTURBED ground nearby, only in the Christmas tree field 
(birches, Buddleia, Pentaglottis sempervirens) and in the margins of 
the garden or edge of the driveway (sweet woodruff, California poppy, 
Campanula rotundifolia [almost native here], Calluna vulgaris, 
Geranium pratense, Campanula persicifolia, Polygonum bistorta, 
Meconopsis cambrica, Helleborus argutifolius,. Dianthus deltoides). 
The worst mistake was planting Pentaglottis (Boraginaceae), which a 
nursery sold misidentified as Brunnera; it is very difficult to 
destroy, requiring several years of herbicide spraying, and it has 
foliage lush enough that it might interfere with native herbs, though 
not with the woody species that naturally dominate the plant 
community here. It has spotted leaves and deep blue flowers, and I've 
had some real arguments with people who saw it and wanted me to give 
them seeds of it, which I'd never do.

When "invasiveness" is evaluated for regulation, however, it is done 
on the basis of whether a plant spreads in cultivated conditions -- 
and given a hospitable climate, almost anything will.

None of my bulbs has become a threat to the native community, 
although in the open fields (not a natural part of this environment) 
one sees Muscari and Crocus flowering here and there, from seeds 
distributed by ants.

Jane McGary
Northwestern Oregon, USA

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