By Alan McMurtrie
one thing I particularly like about Irises is how beautiful they are: modern
Tall & dwarf bearded, Juno and Reticulata species and hybrids, Evansias such as milesii, Arils, Spurias,
Siberians, etc., etc. They are quite diverse,
and each group is quite fascinating. All
of the different types can provide bloom right from the end of March when the
snow is just disappearing, right through to mid July. There are even a few Bearded Iris and
Siberians that with good conditions can "rebloom"
in the Fall. Of course what also helps
is the fact Irises are perennials, so in most cases I can just plant them
outdoors and leave them alone.
would have to say that both Siberian Irises, and Junos tie for being the easiest
Irises to grow. Siberians can be left
for years in the same spot without dividing, and they don't tend to be bothered
by Iris bore like bearded Iris.
Eventually a Siberian clump will thin out in the middle giving you a
"donut". You don't really notice this
due to the leaves and flowers arching over a bit. Colours range from
pure white to lovely blues, violets and purples, with better yellows and pinks
continuing to be developed, along with new patterns.
are easy, particularly bucharica, magnifica and many hybrids which are
mistakenly sold under species names.
They can be left in one spot for years and will reach an equilibrium
number of bloom stocks. As well, they
seem to be able to take soils ranging from sand to clay; they just don't like
wet spots (except from snow melt in the early Spring when they're in growth).
and Dutch Irises
in Toronto I use to grow quite a few Dutch Irises; several hundred as a matter
of fact, and I had quite a few seedlings coming along. However one Winter 98% were killed. I did try some a few years later. They didn't last very long outdoors, so I
wouldn't recommend them. It's unfortunate
garden centers promote them for Fall planting; they should really just be
planted in pots and enjoyed indoors.
Irises on the other hand are quite hardy, and do well. They need a bit of moisture during the
Summer, so I have mine at the front of the house were, along with some annuals,
they are given an occasional watering.
The only problem is, they are susceptible to virus which shows up as
streak marks on the flowers. Because of
this, commercial growers tend to shy away from them, making them hard to
find. I particularly like the pale
are my passion. Many times I've heard
people say that Reticulatas don't do well for them. I have found something similar. As an experiment I bought 12 danfordiae and 12 Iris reticulata hort. several years ago. The first year I got 12 blooms on each, just
as expected. The second year, each had
24! The third year however there were
only 6 on Iris reticulata hort., and
none on danfordiae! The fourth year there were only 5 on Iris reticulata hort., and likely none on danfordiae. To me what this says is they need to be
replanted every year; afterall they were able to give
twice as many flowers in their second year.
At that point however the bulbs were too crowded and were not able to
grow bloom-sized bulbs. There many be
other factors coming into play as well, since the number of leaves dropped off,
which suggests disease destroyed some of the bulbs. Crowding may have encouraged the disease.
am working to produce more robust hybrids, along with new colours,
patterns, etc. Unfortunately this
doesn't happen overnight: it takes 5 years to go from seed to first bloom. And most of the parents available are at, or
very close to the species level (meaning there isn't much variation in the
progeny characteristics). As well, once a
good clone is developed it takes many years to build up stock of it: with doubling,
in 10 years you have only 1024 bulbs (that's 15 years after the cross was first
made!) With another 5 years that
increases to just over 32,000 bulbs: now you're getting somewhere! In Holland, commercial growers think in terms
of hundreds of thousands of bulbs, or even millions.
is unfortunate that Retics are not more commercially available here in
Canada. There are many good varieties
that I've never seen offered in the Canadian market. The newly opened Canadian office of Jacques Amand Ltd. did however offer an extensive list of them last
year. Hopefully more people will become
aware of this firm.
To Frertilize Or Not To Frertilize
bit of fertilizer never hurts: both in the Spring and Fall. Be sure though, that it's low in nitrogen
(the first number on the package should be lower than the other two eg. 7-7-7 or 4-12-8).
Cygon with a vengence to irradicate
any infestations you might have. It's
always best to spray once in the early Spring before much leaf growth gets started,
and once more about a month later.
Problems with Iris bore can be detected by the center leaves of a fan
starting to turn brown. This is due to
the Iris bore having completely eaten through the leaf. By this time however it is too late to spray.
Your only solution is to go after the
critters by hand. A quick and dirty
approach is to simply cut off the leaf fan at the base of the rhizome (not the
best for the plant mind you). I If the
bore has already gotten into the rhizome, then it's a matter of assessing how
valuable the rhizome is. If you already
have a lot of it, the easiest thing is just to toss the whole rhizome in the
garbage -- make sure the bore doesn't fall out on the way to the garbage can! If it's a valuable one though, you'll want to
dig it up and dig the bore out with a knife.
If you catch them early enough you can simply squish them between the
leaves (spread the leaves apart and pry the sides up to find out where the bore
is, and thus know where to squish).
spot (brown spots on the leaves) doesn't hurt the plants, but it doesn't look
nice. Also, Agriculture Canada tends to
frown on it if your wanting to export your rhizomes (though generally any spots
get cut off when the rhizomes are trimmed for shipping). To reduce leaf spot considerably, include a
bit of Captan or Benomyl in
your sprayer when you're spraying for Iris Bore. It's best to alternate between the two from
year to year.
Iris for a show is fairly easy. On the
day of the show pick only fresh stalks -- ones with flowers that have opened
within the last day. If you look at your
Irises critically, you can see how much nicer ones with fresh flowers
look. If you have to, the only time that
you can get away with picking stalks with finished or nearly finished flowers
is if they can be removed without anything looking amiss. You would only want to do this if several of
the stalk's other flowers have just opened.
Break off the old ones right where they attach to the stalk. Be careful not to damage the spathe so that
everything looks natural. Plus be sure
that the fresh flowers look pristine eg. no
"juice" on them from the spent flowers.
stalks in hot water can help open flowers, similarly ice cold water can help
hold the flowers as they are. A fast
setting glue can come in handy to some repairs, such as to spathes.
transport your flowers you will need a bucket with its bottom half filled
somewhat tightly with old rolled up newspapers; and of course some water. Be sure that the bucket is held securely when
transporting it in a car or van; you never know when you might have to stop
suddenly. Make sure none of the flowers
knock against anything solid if the vehicle were to hit a pot hole.
reason for replanting is to keep your Irises blooming consistantly
year after year. They can't do that if
they have to compete heavily for limited nutrients, or if they can't get many
roots down because they're on top of other rhizomes.
best time of the year for dividing most Iris is Summer when they are
dormant. Siberians, Spurias,
Pacific Coast Natives (PCN), and a few species prefer being divided in Spetember or October when the fall rains have started. You can however replant at any time, though
this year's bloom will be affected if you do so early Spring, or next year's
bloom will be affected if you replant late in the year. Also, you will probably find with some Iris,
it may take them a year to get re-established.
That's a small price to pay for their improved performance. Sometimes you just don't have a choice about
replanting, its got to be done now, and that's that. Of course replanting with a minimum
disturbance helps. For example, digging
a clump then immediately planting the largest pieces in a previously prepared
particular, bearded Irises that need to be replanted every 3 to 4 years
depending on how close together you originally planted them. Spurias, Louisianas and some species Iris will also need replanting
about that often. I would recommend
replanting Reticulatas and English Iris every year if possible, or certainly
every two years. Smaller bulbs should be
planted closer to the soil surface than large bulbs. Be sure to take note of how deep the mature
bulbs had been.
rhizomous Iris, dig up the clump, then cut off the
largest leaf fans with 2 to 3 inches of rhizome. Plant no more than 5 with their leaf fans
facing outwards (toes together). If you
have the space you may want to plant 3 in the centre,
and then 3 or more in a second ring. Be
sure to trim the rhizomes leaves before planting them so they don't fall
over. You will be amazed at how many
rhizomes you have left over -- how did they all fit in that spot? Don't replant too many or you will need to
replant them again sooner. Remember the
smaller pieces will take a year or more to get up to being bloom-sized. A few large rhizomes are far better than a
lot of smaller pieces that may not bloom.
some on to a neighbour, but only if he or she is
going to look after them. The last thing
you want is Iris bore from their clumps to invade yours!
late October it is very important to be sure to mulch newly planted Iris with
leaves or straw in order to prevent them from heaving out of the ground due to
Spring freeze-thaw cycles. Even if you
planted them in Summer they still don't have a well enough anchored root system
to prevent heaving. Also I have fround it dramatically
cuts down on rot.
the mulch in early Spring; certainly by the time the Retics have finished,
which is the end of April here. I remove
mine perhaps 2 weeks earlier than that.
Of Loosening Your Soil
seems to help tremendously if you give your soil a good digging when you
replant. I know I often see a youthful
vitality return to my Iris. This is true
even if I haven't been walking on the garden (just on stepping stones). The soil gets compacted over the course of a
couple of years.
To Do If Rhizomes Develop Rot
scoop out the rot with a spoon or other implement, trying to get as much of it
as possible. Then toss on some powdered
material such as Agricultural Gypsum to act as a drying agent. A small amount of powdered cleanser may work just
as well. Usually rot rears its head only
in the Spring. With moist conditions at
that time of the year, the affected area won't likely be able to dry out on its
own. Left untouched it will wipe out the
just point out that with older plantings, you'll find the oldest rhizomes
rotting. This is natures way of returning
the useless tissue back to the earth.
The rot does not spread to the newest tissue, and thus is not cause for
always fun to try your hand at making a few crosses. Pick two parents you really like (try ones
with different colours so that the progeny will be
more interesting -- you can't expect much more than blues if you cross two
blues). Be sure to do more than one or
two crosses, since only about 50% work.
Also, I would highly recommend labelling the
crosses (pod parent by pollen parent).
Collect the seeds just as the pod is starting to open (it's tip turning
brown), and plant them in a spot where you can leave them undisturbed for at
least 3 years. Mark the crosses on metal
tags if you can; plastic ones become brittle in sunlight and are then easily
broken, though they can be put below the soil surface where they'll last
considerably longer but will be difficult to find. I highly recommend making a map on paper to
show the rows and which crosses were planted where. It's quite possible that one or more of the
tags may accidentally get pulled up without your noticing, for example when
removing the mulch covering in Spring
it's wise to mulch the seeds to prevent sudden cold snaps from killing the
seedlings eg. a week of warm weather in which the
seeds start to germinate or the seedlings start back into growth, followed by a
sudden, deep cold snap. They are quite
venerable, since they are so close to the soil surface. The mulch also prevents seedlings from getting
heaved out of the ground.
A Few New Iris
an effort to purchase a few new Iris this year, particularly types you don't
currently have. You will be well
rewarded for your effort!