to the iris forum, bron.
we do have some forum members who live in your hemisphere, although, i am afraid i don't know how close they live to you.
i live in southern california about 1 1/2 - 2 miles from the pacific ocean. we are not considered the most ideal growing climate, but i've had moderate success in getting my irises to bloom. i've had to work hard at it. we have very sandy soil, and have a monsoon season with bouts of high humidity, and our summers have been relentlessly hot (especially these last couple of years).
while i've noticed that the irises i bought 2 years ago have declined a bit, i think the remedy is to add more compost. i may have to dig the iris clumps sooner than 3 years because my soil is nutrient starved.....i am presently, working on this matter by digging up older clumps and filling back with more compost and worm castings. it's a work in progress.
i don't know if we are considered subtropical, but i am able to grow plumerias, anthyriums, cordyline fruticosa, phaeleonopsis, and other orchids not usually grown outdoors (other than in hawaii or in the tropics), passion fruit vines and many other plants without the aid of shelter with the exception of very cold winters.
