BEARDED IRIS

Gar­den favourites for more than a hun­dred years, th­ese stat­uesque beau­ties still cap­ture our hearts.

Canadian Gardening Annual 2016 - - Profile - Text STEPHEN WEST­COTT-GRAT­TON

TO­GETHER WITH LILACS AND PE­ONIES, BEARDED IRISES have long been con­sid­ered an old-fash­ioned gar­den sta­ple, so much so that even non-gar­den­ers can put a name to them, and iris-smit­ten artists from Monet to Van Gogh have filled their can­vases with th­ese uniquely formed flow­ers (ver­ti­cal stan­dards with droop­ing falls) and their rich stained-glass hues. But mod­ern bearded irises have come a long way since the late 19th cen­tury, when those artists were im­mor­tal­iz­ing them in paint: To­day’s cul­ti­vars are avail­able in vir­tu­ally ev­ery colour ex­cept scar­letred and true blue. Some va­ri­eties sport solid colours (known as “selfs”) while oth­ers are a kalei­do­scope of con­trast­ing hues, and the beards for which th­ese plants are named are now larger and more colour­ful. Many va­ri­eties are fra­grant, some

˚ even re­bloom, and all mod­ern cul­ti­vars have thicker, stur­dier pe­tals than their wild coun­ter­parts. The bearded irises we grow to­day are prin­ci­pally de­rived from just two species: the blue-flow­ered Croa­t­ian or­ris root (Iris pal­l­ida) and the yel­low and white Hun­gar­ian iris (I. var­ie­gata) with its in­tri­cate ve­na­tion. Where th­ese two species meet in the wild, they pro­duce a nat­u­ral hy­brid which was for­merly clas­si­fied as a true species (I. ger­man­ica), hence the alternate com­mon name, Ger­man irises. Bearded irises have been grown in Euro­pean gar­dens since the 15th cen­tury, and grad­u­ally gar­den­ers be­gan se­lect­ing flow­ers with un­usual pat­terns and colour com­bi­na­tions. In 1822, the first hy­brid bearded iris (named ‘Burien­sis’) was in­tro­duced in Paris. For the next 60 years, hun­dreds of French cul­ti­vars were raised from open (in­sect-pol­li­nated)

crosses. Need­less to say, th­ese fetch­ing French flow­ers soon at­tracted the in­ter­est of English gar­den­ers, and the sin­gle big­gest break­through in iris breed­ing took place in English phys­i­ol­o­gist Sir Michael Foster’s (1836-1907) back gar­den.

In the 1870s, Foster be­gan cross­ing com­mon bearded irises with four newly dis­cov­ered species. Un­like I. pal­l­ida and I. var­ie­gata, which are both diploid (each hav­ing 24 chro­mo­somes), th­ese new species were nat­u­ral tetraploids with 48 chro­mo­somes. When diploids and tetraploids are crossed, they usu­ally pro­duce ster­ile (or “mule”) flow­ers, re­sult­ing in a breed­ing dead end – but, mirac­u­lously, Sir Michael’s crosses pro­duced fer­tile tetraploids with big­ger flow­ers, thicker pe­tals and highly sat­u­rated colours (much like tetraploid daylilies).

Now the game was afoot, and Sir Michael quickly re­leased six cul­ti­vars which are the an­ces­tors of most of our mod­ern va­ri­eties. While study­ing at Ox­ford, Wil­liam Rick­at­son Dykes (1877-1925) met Sir Michael, caught the iris bug, in­tro­duced new va­ri­eties, penned the first com­pre­hen­sive Iris mono­graph in 1913 and, ul­ti­mately, lent his name to the Dykes Medal, still the high­est award for new iris cul­ti­vars.

By 1925, iris hy­bridiz­ing had be­come a se­ri­ous busi­ness in North Amer­ica, es­pe­cially in Ore­gon. In this re­gion, breed­ers col­lab­o­rated openly, gen­er­ously shar­ing their knowl­edge to­ward the com­mon goal of pro­duc­ing im­proved bearded iris cul­ti­vars. Re­search into de­vel­op­ing re­bloom­ing bearded irises was pi­o­neered in the 1970s by Dr. Lloyd Zur­brigg, and while re­bloomers are still a rel­a­tively re­cent phe­nom­e­non, breed­ing is on­go­ing, and twice-blooming irises may soon be­come the norm for th­ese ma­jes­tic flow­ers.

in na­ture, iris “beards” act as pollen guides to steer for­ag­ing bees in the right di­rec­tion, but in the ab­sence of in­sects, they also help to trap pollen, en­abling the self­fer­til­iza­tion of in­di­vid­ual flow­ers. ‘rasp­berry blush’ in­ter­me­di­ate bearded iris

‘NAPLES’ TALL BEARDED IRIS ‘BLUE SUEDE SHOES’ TALL BEARDED IRIS

‘IM­MOR­TAL­ITY’ TALL BEARDED

IRIS

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