Is it safe to assume that plants that suffered from rust in zone 8b can be dug up in the late fall (October?) and donated to friends who live in zones 5 or 6? I assume that winter there will kill any remaining rust spores but want to make sure before I offer plants to anyone.

Zone 5 would be safer than Zone 6 in case they are actually Zone 7 which is the rough rule-of-thumb zone where rust may or may not survive depending on the year. Planting close to a house wall with a protective winter mulch, for example, could also put the leaf bases in a warmer microclimate.

The downside is that in colder areas October may be getting late for planting outdoors.

As an aside, you don't just have to be concerned about spores surviving, daylily rust can also survive as an existing but non-sporulated infection inside the leaves where the fungal body cannot be seen. In an area where all foliage is killed to the ground that should not be an issue because rust cannot survive long in dead tissue.

I certainly can dig them up earlier. September would be fine. I would only donate plants to friends who live where the winter is very cold, and all foliage would definitely die. The friends I'm considering offering them to are in zones 5b and 6a.

I won't consider this if there is any significant chance of spreading rust. It's just that some of my plants were very lovely, and I hate to just throw them in the trash if there's a chance someone else could enjoy them.

What you could try is... Cut your folliage in half, water the plants roots extremely well, and start spraying the plant with hydrogen peroxide 3% mixed with water. Use a ratio of around 10 % hydrogen peroxide to water, it does not need to be precise. Do that about every 4 days. Let the mixture run between the fans, and get the undersides. That will start to kill off the active rust. Before shipping do one of two things. Either give the plants a bath in hydrogen peroxide, or dish soap water. For hydrogen peroxide up the quantity to 25 percent hydrogen peroxide with water. Dish soap and some baking soda, skip the oil, and follow an internet recipe. This will greatly reduce the possibility of a problem.

And I am sure you are letting your friends know that you had rust, so they can decline your offer. Otherwise there might be a southern grower, who thinks they can work with the plants. I would not just destroy them. I was given two rusty plants kept them two hundred feet away from my other plants. I kept washing them, pulling folliage off, they went heat dormant. It is true new rust does not develop here in temperatures over 86 degrees. Washed them as new folliage came up, they never redeveloped rust.

Many blessings for your success!

Yes, I am planning on being very transparent about the fact that I have had rust in my yard. Some of the plants I'm donating haven't gotten rust but are simply not thriving, and I think they may benefit from a colder climate. Others were beautiful plants but have gotten rust several times, and I want to replace them with cultivars I am hoping will be less prone to rust.

Thanks for the strategy. I will try it.

I used to trade with someone years ago from Arizona, i think. She sent me plants with rust, sometimes they looked quite bad. I never had rust overwinter here, even in the mildest of winters. Of course, zone 6b in Ky is not always equivalent to 6b in another state.

That's very encouraging, Nancy. Thanks.

And if anyone here is interested, send me a tree mail. I don't have anything really fancy--mainly older cultivars, but some of them were quite lovely.

I think your offer is very generous, and if you openly give the disclaimer of having had rust, it should be sufficient to trim and ship . With people in zone 5, if you could ship in early to mid September, that would increase the chance of plants surviving. New plants coming from this south must have time to settle in and form some new roots before the ground freezes. It would be kind to suggest they might want to dip the plants in a 10% Clorox solution before they plant.

Thanks for the tip on shipping, Julie.

What do you think about using the bleach dip before shipping? I've never done this before and would appreciate more directions. Do you dip the entire plant in, or just the roots? How long should the dip last? And do you rinse afterward with plain water?

DeweyRooter said:Thanks for the tip on shipping, Julie.

What do you think about using the bleach dip before shipping? I've never done this before and would appreciate more directions. Do you dip the entire plant in, or just the roots? How long should the dip last? And do you rinse afterward with plain water?

Based on this study there is no point in dipping the roots, see sodium hypochlorite results in Table 2:

https://apsjournals.apsnet.org...

Dipping the foliage in bleach may kill spores on the leaf surface but not any non-visible fungal threads inside the leaves.

However, if climate in the colder zones kills the rust anyway, do we really have to worry about it?

Zoia said:However, if climate in the colder zones kills the rust anyway, do we really have to worry about it?

I am just trying to play it safe!