Iris cristata and other small woodland Iris

[TheOnionMan]

Having never harvested seed on Iris cristata, I've been wanting to do so, as an experiment to see if seed-grown plants show any variability.  I also needed to learn how to harvest the seed; when is the seed ready?  Every few days I've been picking a pod and snapping it in half to test the progress of the developing seed inside.  Today, I think the seed was ready as a few pods started to show a small degree of whitening in color, and a few other pods had actually dropped off (although remained unopened), surely ready to pick.

I harvested the seed on I. cristata 'Sam's Mini', a low growing variety found by Sam Norris of Kentucky.  On the photo showing the seed pods, those on the right show the lobster-claw like leaf bracts that each hold twin seed pods, the long styles are persistent.  Initially when testing seed for readiness, they were nearly clear or translucent... so I waited until they were a semi-translucent to nearly opaque tan or yellow color.  Harvesting the seed is as easy as snapping the pods in half, then gently squeeze the seed out.  They were sown fairly thick in flats, covered with fine decomposed pine back mulch, covered with wire mesh to prevent digging by chipmunks and squirrels, and they'll spend the year outside, hopefully to germinate next spring.

I have included photos to show what this plant looks like in flower, and when first emerging.  The rhizomes run on top of the soil, in fact, they prefer to slowly romp through the top layer of woodland duff or well decomposed bark mulch.  In this particular cultivar, the rhizomes amusingly look like they're leaping up and over like spawning salmon as they progress forward.

[Lesley Cox]

That's one helluva lot of seed Mark. I'm lucky to get even one pod! I would probably have left the pods until they were starting to brown or even starting to open at the top.

[TheOnionMan]

That's one helluva lot of seed Mark. I'm lucky to get even one pod! I would probably have left the pods until they were starting to brown or even starting to open at the top.

The pods of Iris cristata really need to be picked in the green, when they are just starting to lighten in color or start turning whitish; snapping a pod in half reveals whether the seed is ready or not, color should be a pale yellow.  These are different than, let's say, bearded Iris species, where one can leave the pod to dry and start splitting open.  Also, it seems on the green succulent types of pods of Iris cristata and some Chinese woodland irises, they are highly attractive to some sort of insect that can get to the seed before harvesting, and to chipmunks/squirrels that like to munch them, so early harvesting when the seed is indeed ripe enough makes sense.

Today I harvested seed on Iris cristata 'Edgar Anderson', a relatively giant form of cristata, which flowered the same time as the yellow Iris koreana, making me wonder about possible hybrids.  Got a large batch of seed, all has been sown.  Most other Iris cristata varieties bloomed later when we had very hot days to 94-95 F (35 C), and as a result the flowers went by in just a couple days, and almost no seed set on those.  Got one seed pod on I. cristata alba, which I sowed next to the mother plant.

I show two photos of the mats of surface rhizomes back in early April, with the new growth more erect than most Iris cristata forms.  One can tell from the start, that the cultivar 'Edgar Anderson' is going to be larger than most cristata forms, based on the vigorous tall shoots.  Then two photos from this May of the beautiful blue flowers.  The last photo, of a small I. koreana that started flowering a few days before I. cristata 'Edgar Anderson' but both species with flowers open at the same time.

[TheOnionMan]

I've never had good luck harvesting seed on Chinese Iris species.  It helps being retired (wish I was) or unemployed (wish I wasn't, sort of), because I get to observe in much more timely detail, about what plants are up to.  Year after year, I see big, fat, 3-sided pods on species like I. koreana and I. odaesanensis, two wonderful Chinese woodland Iris species, but rarely ever get any seed, although do find seedlings of I. odaesanensis here and there.

So, I discovered that the seed pods are much like other ephemeral seeders such as Jeffersonia, Epimedium, and Corydalis, they are actually ripe and mature when they're still green, when they are "al dente" and not "fully cooked", but even more so with I. koreana.  Harvesting the large seed pods while green (noticing that a few had gone over to yellow, but with nothing inside), and snapping the green pods in half, there's good seed in there, like golden kernels of corn with starchy appendages (elaiosomes) that are attractive to ants.

So, I harvested seed on Iris koreana, odaesanensis, and henryi much earlier that I would normally, and found a good percentage of viable looking seed.  Time will tell whether my early seed sowing efforts are the proper recipe for success.  Iris koreana was blooming at the same time, and within close proximity of I. cristata 'Edgar Anderson', so I'm interested in finding out whether the bees were up to any hanky-panky.

[Lesley Cox]

I. koreana is a honey Mark. Closely related to I. minutoaurea? which doesn't flower well for me. You are fortunate to get that lovely seed.

[TheOnionMan]

I. koreana is a honey Mark. Closely related to I. minutoaurea? which doesn't flower well for me. You are fortunate to get that lovely seed.

Iris koreana does a pretty good emulation of I. cristata, only with yellow flowers.  Darrell Probst tells me that he has tried crossing the two species, but thus far no hybrids.  One reason I'm interested in growing on the seed, maybe the bees have done it better.

Iris minutoaurea took several years to "settle down" before it started to flower well.  This year was a fairly good flowering (2 photos), but the plant is being encroached upon and shaded by Epimedium x setosum; must move the Epimedium to afford more room for the Iris. No seed again this year, it got very hot when the plants bloomed and they went over too quickly.  I always forget to use some sort of scale object when photographing this plant, as it is so tiny in flower that it is hard to capture a sense of scale.  Both I. koreana and I. minutoaurea have the undesirable habit of expanding their foliage significantly after flowering, making larger (and untidy) foliage clumps than one anticipates, as compared to I. cristata that maintains the spring foliage size (last 2 photos).

[mark smyth]

My cristata - sp and alba - have never set seeds

[mark smyth]

This year my I. cristata and the white form had a only two flowers each 

[TheOnionMan]

This year my I. cristata and the white form had a only two flowers each 

Mark, do you grow them in pots or outdoors?  I have never grown them protected in pots, but have heard they are not the most amenable creatures for pot culture.  Of course outdoors, where slugs are a problem, that can be a challenge too.  Here, they are among the easiest and most satisfying Iris to grow, rapidly spreading and flowering prolifically.  The mistake people sometimes make with them, is planting the rhizomes too deep, as you can see in the rhizome views I included, they like to run right on the surface, so are best planted in a layer of woodland duff or decomposed bark mulch.

Typically they make lots and lots of seed, but I've never bothered collect seed until this year.  My large mat of I. cristata 'Shenandoah Sky' growing under a Stewartia pseudocamelia tree, flowered prolifically as always (photo from 2008), but with several days of unusual heat (94 F - 35C) the flowers went over quickly and made no seed at all, I suspect because the process of fertilization did not have enough time as the flowers were toasted.

Same thing with two newbies in the garden, I. cristata 'Mountain Girl' and alba.  Both were planted last year, as 2-fan starts, and I'm pleased with how much they grew in one year, and flowered this spring, but the flowers were no match for the heat (photos of each)... I was lucky to get one pod on alba even with the heat.  The one named 'Mountain Girl' is a 2007 introduction by Joe Pye Weed's Garden (Marty Schafer & Jan Sacks, breeders of amazing Iris), lovely light blue flowers lacking any yellow among the white signal patches.

[mark smyth]

My lecustris is in full shade and flowers very well but never sets seeds

I cristata blue and white are in full sun troughs

When can I remove rhizomes for sharing?

[PeterT]

The new fans are starting to root now Mark. I can confrm that they do not grow easily in pots, last year I germinated some cristata but they scorched. 
Does I koreana grow in just the same conditions? I have a small pot of minutoaurea and a couple of clones of koreana plus seedlings from last years SIGNA seed. I henryi and gionocarpa have also proved tricky in pots and I am thinking of planting them out? advice please

[mark smyth]

THanks Peter.

[TheOnionMan]

Does I koreana grow in just the same conditions? I have a small pot of minutoaurea and a couple of clones of koreana plus seedlings from last years SIGNA seed. I henryi and gionocarpa have also proved tricky in pots and I am thinking of planting them out? advice please

For several years my I. koreana barely flowered and shrank in size, so I moved it a couple years ago to a new location.  I believe it was too dry where it was; the new location gets more light and has better humus-rich soil that is more moisture retentive, and it has jumped in size, flowered well, and set lots of seed.

Interestingly, Garden Vision Nursery this year (2010) offered pre-sales on I. koreana "Select", reported as a "very floriferous clone" and "one that propagates well", promising that a cultivar name will be registered before the fall shipment.

I will follow this post with another that shows how I. henryi and I. odaesanensis grow.

[TheOnionMan]

I have I. henryi and I. odaesanensis growing on a rather dry enbankment, I. henryi seems to love the location, with about 200 blooms this year (but only 4 plump seed pods) and for some reason just this year, I. odaesanensis barely bloomed at all, I think just 3 flowers, although the plant has spread to about a meter across and looks healthy otherwise.  I might split it and try growing some pieces in a more moist location.  Iris koreana didn't like the dry location at all, and now prospers in a more moist location. I. henryi and I. odaesanensis seem to grow as "turf" species, the old foliage persistent (evergreen, but still persistent in I. henryi), and in spring grow out of the mass of older foliage.  Some photos to illustrate the progression:

1   March 2010, enbankment with I. henryi on the left, the evergreen foliage trailing down nearly 2' (60 cm), with the dead persistent foliage of I. odaesanensis on the right (don't even think about foliage cleanup, not worth the tedious effort).

2   Late April 2010, the plants coming to life, I. henryi budded (lots of buds), and new foliage of Iris odaesanensis in the background, taking over the persistent old foliage.

3-6 Iris henryi, lots and lots of bloom, about 200 flowers.  This is a bi-flowered species, and a couple days after the first flush, it repeats itself with a second flush of the same number of flowers.  The flower color is the palest smokey blue, hard to capture in photos, but it is exquisite.

7   I. henryi, setting lots of pods, but a false promise, as only 4 out of hundreds of pods would end swelling into a round lime-like ball to produce seed; in this photo one swelling pod can be seen.

8   Foliage of I. henryi and odaesanensis taken today, really good on a slope where the foliage hangs down to follow the slope.

9   A photo from October 2008, showing the enbankment after we've had some frost, the very narrow grass-like leaves of I. henryi on the left looking very much like the leaves on Carex caryophyllea on the right, with the turfy mass of I. odaesanensis taking on some yellow frost-induced color in the center.

[PeterT]

Thanks Mark, some great information so that I can translate it to UK conditions - are your winters exceptionally dry or wet?