Siberians will do fine zone 8. So should most other kinds of iris. There are many posters here from California and other locations even more mild than zone 8 that are able to grow various iris very well. Summer humidity or specific planting conditions may limit how well some grow, but I doubt it has much to do with mild winters :-)

Siberians grow fine in ordinary garden soil with decent drainage - they do not require excessive moisture. I grew Japanese iris in regular soil as well, just with ordinary irrigation in our dry summers. Most iris will need dividing after a few years - with the beardless varieties, which is mostly what I grow, the center of the clump will begin to die off and the flowering will reduce. When that happens (3-5 years typically), the clumps need to be divided and the old, woody center portion discarded.

FWIW, 'Caesar's Brother' is a fine, reliable selection of Siberian but it is kind of just a basic, purply-blue iris -- a bit boring. There are dozens of other cultivars that offer more and better coloring and patterns.

Hi
Not sure where you are in coastal NC, but I'm in coastal SC (Horry county), and bearded iris do very well. YOu noted that you had bearded iris which were shorter. HOwever, if they have the right soil and good sunlight, they will grow very tall. I would imagine our soils might be similar.

Good luck

Mike in SC

Thank you, gardengal and mike. I read somewhere online that if some bulbs, (iris were one) did not have a cold enough winter that the stem would be short, so that's why I thought it was just too warm here. But, it was probably a lack of nutrition (the sand sucks moisture and nutrients down, though I add mulch and compost every yr.)
Mike, your climate and soil probably is comparable to mine, where do you buy your flowers from? Most of what I buy comes from Bluestone, and I get bulbs from Brent & Beckys. I'm always looking for a new, good source... Thanks, Brandyray

I am on the borderline of Zone 7B and 8A. For the last fifteen years we have been having Zone 9 and even 10 winters, but this year we have been in the deep freeze since Thanksgiving. We had snow in the morning yesterday; then the sun came out. By 4 p.m. the clouds were back and it was snowing again. Not our usual pattern.

Siberians, for the most part, are a failure here. The heat of summer with high humidities is what gets them. Caesar's Brother is the only one you can count on in heat and high humidity. I have spent a fortune on the new Sibs from Joe Pye Weed's Garden and have lost every one of them. If you can find somebody locally who has 'naturalized' other varieties, try to get those. They probably would be older varieties. I have found Sibs really need afternoon shade in a hot, humid climate.

Good luck!

There are bulbous iris and non-bulbous iris :-) Bulbous iris like the reticulatas and Dutch are true bulbs and like most early blooming true bulbs do need a chill period to develop good flowering. Bearded iris are not technically bulbs - the rhizome is really a modified stem and heat or cold should not have any significant effect on how it or the stems emerging from it develop. Not at all the same kind of embryonic storage organ as a true bulb. And Siberians and many other beardless iris are just fleshy rooted perennials, very similar to daylilies in their root structure.

A bit confusing......I can't think of many other plants that offer such a range of different root or root support structures.

Thank you, wm., that is exactly the kind of info I needed. Maybe the Caesar's Brother will do okay here. I will be planting it in my bulb garden, and that is an area that gets watered more than most of my yard.
Thank you for the info, gardengal. My mother had about 300 bearded iris at one time, but they are a rather formal flower to me and I like the looks of these smaller varieties. Maybe they fit in w/ my tradescantia (spiderwort) better too. As for Daylilies, they have done well for me so far. Brandyray

All the climate zones do is represent the lowest temperature.

You cannot make a blanket statement that Siberians will grow in Zone 8 period (I mean all across the country). They will not grow just because you live in Zone 8.

The zone classifications are determined by the average lowest winter temperature and do not take into consideration heat, humidity, or rainfall.

Out west Siberians may thrive in Zone 8, but if you live in a Gulf coastal Zone 8, forget Siberians except for Caesar's Brother and a very few others. I live 300 miles inland from the Gulf, and they will not thrive.

Thank you, wm. It sounds like I ordered the right variety. Also sounds like our climates are somewhat similar, are there other bulbs you would recommend? Brandyray

This pretty interesting how these are difficult for some areas in zone 8. I live in Zone 8b in South Carolina (about 75 miles inland from Charleston so I'm definitely in a warm, humid area. Siberian iris are a top performer for me...tough as nails, reliable, no pests, etc. I've had them 20 plus years and moved them all over my garden, and given them away by the wheelbarrow. I got my originals from a fantastic gardener who had a stunning landscape (grafted his own camellias--way above my head). I have also added to them from some of the newer cultivars...just added several new ones last fall from a nursery in Oregon. However, I have a fairly heavy soil (not clay, though) that actually holds water in several places when we have alot of rain (like this winter---16 inches in 2 months). I wonder if it has more to do with the soil, and less to do with the temperatures. I have included some pictures (I hope they copy correctly) so you can see that they actually do thrive in this climate. I would agree with gardengal, they do require periodic dividing, and it is a job...big heavy root ball leaving a big hole you have to backfill with something. Actually, this usually when I just give the whole clump away. They also reseed around which can be a good thing. They have good foliage that looks nice all season and is a good background for other flowers that may not have such good foliage.

Thank you, br. Your pics are great and the iris really show up. I think the Caesar's Brother will do well for me.
You may be right about the soil. My roses have done well so far but they are planted on top of the drain field and the clay there helps them hold onto moisture, the rest of my yard is sand. I will just have to water my bulb garden more regularly, and maybe I will plant some iris in w/ my roses. Thanks, Brandyray

This is one variety that looks like Caesar's Brother, which is the exception and will grow almost anywhere.

Have you tried any modern Siberians from Joe Pye Weed?

Beautiful garden, brpinson. Thanks for sharing it with us.

No, wm, I had never heard of that nursery until you mentioned it. I have been ordering from Brent and Beckys, and also Gilbert H. Wild. Since you mentioned it however, I looked it up, and they certainly have a large selection. Color-wise, I liked Mister Peacock, Over the River, Sporting Chance, and Caitlin's Smile. Are any of these familiar to you? Iris are rather expensive- I am more used to lilies where one gets 3 bulbs for 1 price :) Anyway, I appreciate your feedback. Brandyray

You can grow Pseudacorus and Louisiana Irises in NC. Some varieties such as Black Gamecock will grown in Zone 5. They also don't need to be always wet.

Thank you brhgm. Black Gamecock is a striking iris. I have admired it in catalogs many times. Maybe I will give it a try next year. Brandyray

brpainson,

I haven't bought anything from JPW in about five years because they all died in the heat.

Near your porch post there is a partial bloom of what appears to be a pseudacorus. Right?

You might also try some of the pseudatas. Carol Warner in Maryland sells these. They do well for me. They are crosses between a Japanese iris and a pseudacorus.