I have planted a rose in a heavy clay soil. I mixed in some perlite to hopefully help with the drainage and put some gypsum in the base of the hole. other than that I have not done much. The rose is alive but the new leaves came out deformed and now are yellow and wilting. the leaves at the base look green and happy. Is this a root rot situation? nutrients? maybe a pest? Was thinking about digging it up and actually mixing it in with decent soil but wanted to see what you thought.

The usual advice for heavy clay soil is not to amend it at all. By making the soil in the hole more porous than the surrounding clay, you create a sort of well where water will collect. Roses don't like wet feet.

One area of my garden has incredibly heavy clay soil. In my experience, amending is necessary, but Porkpal is also very right in saying that you don't want to have the rose sitting in a hole of amended soil, whilst all around it is the heavy, unamended clay. This creates what I've hear described as "the bathtub effect",or as Porkpal puts it, a "sort of well". Water will collect there, but ,even worse perhaps is the fact that the plant has no motivation to send roots out to the surrounding soil-it just sits there in it's little hole. I am trying to amend my entire bed, even removing some of the clay, mixing expanded clay and potting soil into the entire area, but I'm by no means certain that these efforts will prove sufficient! Now, maybe your clay is not as bad as mine, and if so ,you might indeed get away with just digging the rose up and re-planting it with no amendments added to the hole-just a nice, generous mulch of organic matter, better yet with a shovelful of manure on the soil surface. Good luck!

The other downside of burying organic material in soil which doesn't drain is that it sours. Like a container whose drain holes clog, the organic material begins supporting the growth of anaerobic bacteria, those which grow in the absence of oxygen. If you've ever smelled "soured soil" you know precisely how to tell if that's happened. There must be somewhere for water to drain out before organic material in it begins to sour or anything planted in it is doomed. Loosening the clay, perhaps adding gypsum as you wrote you did, and digging that clay as deeply as possible to provide air space for the water to penetrate, will help. Mulching well with organic material which will digest and release Humic Acid which will flush into the soil with irrigation and rain will help to loosen the clay further. Those organic particles flush through and separate the "flakes" of aluminum silicate (clay), providing air space and drainage. They must be continually replenished or they eventually wash through leaving clay behind. So, keep mulching. If you can obtain horse manure, use it. Keep it away from the crowns of the plants and out under their drip zones, where rain falls off the canopy of the plants, and keep it watered so the bacteria, fungi and insects digest it, releasing its nutrients and Humic Acid. It's what Nature has done since "day one". It works.

Ok sounds like clay is just a pain in the butt. I'll add the mulch and see if I can not find any manure to put on there as well. would cow work as well or is there something specific about horse? Forgive me, I am experimenting here. I'm such a noob. I have also planted another rose and have mixed 1/3 clay 1/3 garden soil and 1/3 cow manure. Is that rose more at risk at this point? I've tried to make the inside of the hole more jagged and porous before filling so the roots might not have the balling effect. Now I am worried about it!! Lol he seems to be happy for the moment though.

Yes there is a difference between cow and horse manures. It has to do with their stomachs and how it's digested. Cow is just fine to over cover a lawn and work into a vegetable garden soil. It is NOT good for roses unless it is WELL rotted. Burying it in the soil, particularly soil which doesn't drain, can easily lead to it souring and the plant rotting. NEVER bury garbage in a rose hole. Organics digest best where soil temps remain in at least the 70 F degree area; there is sufficient oxygen, moisture and available nitrogen to get the soil bacteria activated. Burying organic material under ground and introducing water generates methane. Many landfills are piped for methane so it can be used as a fuel. Our local hospital has been run mainly on the methane our landfill generates for years. Personally, I would remove the rose planted with cow manure, empty the planting hole and refill it with the clay and garden soil with no cow manure. If you can't obtain horse manure, then use whatever other organic mulch you have available...compost, ground redwood, ground fir, pine, etc. Oak leaves are great, pine straw can be used. Just keep the mulch away from the crown of the roses and out under the drip zone where the water falls off the plant when it rains. That's where the feeder roots will be most concentrated .

You should dig a hole the size of a five gallon nursery can, fill it with water, then time how long it takes for the water to drain out of it. A couple of hours should be fine. A day and longer spells trouble. Anything organic in standing water will quickly sour. That souring KILLS plants. Plant roots require oxygen. The "sour" is the growth of anaerobic bacteria, those which grow in the absence of oxygen.

Over the past 25 years I've planted over 300 roses by digging holes about 15" deep x 15" wide. If the native soil is of high quality (dark and loamy), then I only replace one-third of it with equal parts composted (rotted) cow manure and peat moss, to help with aeration and reduce compaction. If the soil is of poor quality, then I'll replace two-thirds of it with equal parts manure and peat - a ratio I learned many years ago at a course on soil science at the New York Botanical Gardens. I also thoroughly mix RoseTone organic fertilizer with the soil before filling in the hole. This has generally worked well for me across two different homes and gardens, as you can see by the 400+ photos of my roses in the NGA database, some of which can also be viewed here:
https://lens-work.com/public_h...
and also here:
https://www.fleischmannhouse.c...

You should dig a hole, in the same area, fill and I mean fill, with water and check how fast it drains.
Time it takes to drain will tell you what you have.

You should remove ALL surface weeds/grass from an area at least 16 inches in diameter from where the rose is planted, or you will be amending weeds.

I have heavy black gumbo, but it drains well and is very, very good soil, at that, I dig a hole much deeper than I plant IF I am putting a rose in an area where I have not before , OR, if I am putting a new rose in an old location.
I do not want old rose soil in the area I plant a new rose.
I generally use some bagged manure mixed with bagged top line garden soil mixed with native soil from my vegetable garden.