Saturday, February 25, 2012

Not Yet Native of the Week: Gladiolus imbricatus

A gladiolus for Zone 3

As my mythical long-time readers would know, I have been wont to ruminate on the native/alien dichotomy over the years. I’ve chewed the cud long enough that I have pre-digested the problem to my own satisfaction, swallowed my solution, and am ready to spread the results over my gardens and see what happens.
Gladiolus imbricatus
 Yes, native plants can be very nice and tend to be good for native insects and birds, but they alone do not a garden make and some are definitely mistakes (e.g. Jewelweed, Wild Strawberry). Yes, some horticultural creations are monstrosities, and any exotic plant has the potential to escape and grow where we’d rather it didn’t, but if you exercise reasonable caution (e.g. bird and wind dispersed seeds are bad), they do make for a much nicer and no less bug-friendly garden. Also, and I know some might find this controversial, some naturalized former exotics probably fit into their new systems rather well and increase the functionality (e.g. diversity, resistance to disturbance, recovery from disturbance) of the ecosystem.
Bombus vagans or perplexus and European Gladiolus
 Of course, if you define your ecosystems as if they were fixed and immutable and, in North America at least, created before European colonization, then you would probably take umbrage at any plant growing outside its proper place. I don’t share that particular belief system, but I do worry about letting loose something that may damage the environment. This was brought home to me the other day while reading a somewhat obstreperous review of Doug Tallamy’s book Bringing Nature Home (see Books in the Bug Garden sidebar) and the comment flurry at Gardening Gone Wild.
Leaf-cutting Bee enjoying a glad
 One thing that I realized was that I haven’t really done well by the Home Bug Garden exotics. So, herein I start a new series “Not Yet Native of the Week” wherein the pros and cons of plants not yet (or newly) part of the Alberta flora are considered. First up is the flower that enshrouded the ‘big-lipped bee’ in the most recent Pollinator of the Week, the only gladiolus that seems to be able to tolerate Zone 3 winters: Gladiolus imbricatus L. – variously called called the European, Red, or Turkish Marsh Gladiolus. Anyone who has grown the large hybrid gladioli (which need Zone 8 or better to ‘perennialize’) may be surprised to learn that there is a species that can survive our winters, but it is true. A friend gave me a handful of corms in 2006 and I’ve had a small patch ever since.
A denizen of wet meadows and marshes
 The fact that the leaf-cutting and bumble bees like the flowers is good, but also leads to seed pods which I regularly deadhead. This doesn’t stimulate more flowers, but does ensure that tiny gladioli don’t start sprouting here and there. Is that actually possible here in Zone 3?
A pleasant addition to an artificial meadow masking some squash and tomatoes
 Several gladioli are naturalized in North America, but G. imbricatus is not among them and none are listed as noxious weeds. If one casts their net somewhat wider, though, you find that this is not true in other parts of the World. Australia has several gladioli that have invaded roadsides and more intact native habitats and are considered important environmental weeds. I well remember coming across wild gladioli along the trails in Kings Park in Perth – and the disappointment on learning that these spectacular 'wild' flowers were weeds.

Where Gladiolus imbricatus is considered native (SE Europe and Turkey), it can be either a weed of cultivation or a rare meadow plant deserving protection. And, of most interest to us Zone 3ers, in Finland it is listed as a ‘casual alien’. So, I think I will continue to deadhead my gladioli and not plant them where they might escape into a wet meadow or marsh, but I certainly won’t grub them out.

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