arilate irises was bulb rant

Jim McKenney
Sat, 15 Nov 2014 14:07:28 PST
I tried my first arilate irises over fifty years ago; they were the regeliocyclus hybrid 'Chione' and Iris susiana. Both bloomed, but neither lasted more that a year or two more. I still have old Kodachrome transparencies of both (or maybe later acquisitions of both).  Subsequent trials of Iris susiana in pure grit filched from the local railroad tracks (I was still in the thralls of the "good drainage" mentality) resulted in plants which, although they persisted longer, gradually starved to death. 

Years later I tried again with a nice assortment of hybrids (many close to the onco side of things) from a California grower. I still have photos of these, too. When these were received, I noticed something about them which at first puzzled me: it was obvious that they had been grown in clay, red clay. These too did not last long, but wow did they make a deep impression.

When inexpensive and readily available stocks of 'Dardanus' became available in the recent past, I decided to give these plant another try. Several other hybrids and species were obtained at the same time. They were planted in a raised bed of the local red clay. Most grew vigorously and bloomed. Still under the influence of the drainage myth, I assumed that the raised bed (it was raised well over a foot high). Most of the plants, especially the bigger ones which had bloomed, were already rotting when I dug a few in June to check them.  

It was at about this time that I had some exchanges  with John Lonsdale about the culture of these plants. What I took away from that was the use of polycarbonate sheets to cover the plants after they bloom. 

I joined the Arilate Iris Society in 2013, thanks in part to Dennis' preiodic reminders to this list about that group. I obtained fifteen hybrids and planted these out in a simple, ground level (i.e. not raised) cold frame out in a field (my community garden plots) in late summer. All grew and the following year some bloomed. Sometime in May I covered the frame with a glass door (I'm getting too old for this and have since acquired some polycarbonate sheets). All of these (and some other arilates acquired elsewhere) sailed through the summer without a hitch. Many retained their foliage, some became completely dormant. 

In this part of the country, arilate irises ripen during May; guess which month of the year is typically our wettest month? They will never dry out if you don't cover them.  

I got a nasty surprise in September when I removed the glass: no sooner was the clean, vigorous looking foliage exposed to rain than it began to get spotty and die back. 

But the plants are obviously vigorous and otherwise healthy, and I'm already counting next spring's  chickens.

The frame, which might strike some of you as useless, does have a function; it prevents water running across the surface of the ground from entering the framed area.  

In the literature, especially the rock garden literature, there are articles (some of which read like calculus puzzles and kept me tied in knots) discussing drainage. To make a long story short, I think it's largely bunk as far as most summer dormant plants are concerned. What the plants in question need is not good drainage: as long as they are growing actively , they will probably thrive in a pig sty (at least until the pigs get them). But as the time for dormancy approaches, what they need, and this seems to be non-negotionable, is dry soil. That soil can be dried up muck, dried up stable bedding, the local clay dried from its formerly waterlogged condition - the sort of soil doesn't seem to matter, as long as it is dry. 

When these plants are put into very sandy, gritty media they do get rapid water passage; that rapid water passage also takes water soluble nutrients with whatever else drains out. It amounts to a starvation regimen. 

Put them in the richest goop you can get your hands on and watch them thrive - just remember to start to dry them off as they are coming into bloom so that by the time they are entering dormancy the medium around the rhizomes is dry. 

Try it; it has worked for me. 

Jim McKenney
Montgomery County, Maryland, USA, USDA zone 7

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