In the near future I will start to receive some new Tall Bearded iris
rhizomes. As a result of recent over winter survival problems with the
TB's I am planning an experiment of sorts. Last year I lost all
of my new TB acquisition plants. Instead of planting them directly in
the garden as I have done in previous years, I will be planting them in
pots as suggested earlier in the year by some of our loyal fellow Iris
Anyway, here is the plan:
1. receive the iris
2. plant them in approx 6-8 inch pots in a potting soil mixture.
3. grow them in the pots outside until the first killing frosts.
(usually early october here where I live, zone 6)
4. at that time bring them into my unheated garage for storage over the
winter. (until the end of March, beginning of April) This will protect
them to some degree from the wide fluctuations in temperature and drying
winds that can occur during our winters. Can go down to approx 0-10
degrees F in Jan-Feb, but we can also at times have days of 40-50
degrees intermixed. Combined with little snow cover this can be
devasting for iris, especially if they are first year plants.(single
5. As soon as the soil can be worked (mid April), transplant the iris
(just slip them out of the pots, root ball and potting mixture) into the
prepared garden spots. (we have June bloom here, the iris usually don't
start to grow until the start of April)
Now I have three questions for the list:
1. In this particular instance, what are the pros and cons for clay pots
verses plastic pots?
2. What would be YOUR recommendation for the potting mixture
composition? (obviously one criteria should be good/excellent drainage)
The back of Schreiners 1996 catalogue gives a potting mixture of 45%
firbark, 20% pumice and 35% peat moss. What about a mix of vermiculite
and perlite and peat moss?
3. I am also considering storing the potted iris over the winter in a
basement cold room that I have. It would be warmer there than the garage
and they would probably not freeze(but close to it-low 30 degrees F-high
20's) This room is in total darkness most of the time, but then so is
the garage. Anybody got any thoughts on this?
ready to try something new...
Mississauga, Ontario Canada zone6b
Director, Canadian Iris Society
Newsletter Editor, Canadian Iris Society