My theory is that if a rosebush is healthy and blooming normally there is no reason to fertilize. I volunteered at a local public garden that had a section hundreds of Old Roses that had not been fertilized, (or pruned) in a decade. The more a rosebush is pruned, the more fertilizer it needs to build growth to get back to its' mature size. Nearly all the rosebushes bloomed normally, even without any fertilizer at all. There were 200+ classic Hybrid Teas, a dozen or so H.P.s and Bourbons and dozens of Chinas and Old Garden Tea rosebushes. The only rosebushes that did not bloom normally were a c. a dozen that had die-back fungus from poor drainage.

Soil blends.
I dig a hole and put 1/3rd of the native clay in a wheel barrow, the native soil is very important because it stops the bathtub effect, which happens when a hole is filled with amendments that soak up water, with the clay around it serving as a nearly watertight barrier that stops proper drainage.
Then I mix in a blend of the following in the barrow with the native soil.
: blood meal, bone meal, alfalfa meal, a shovel -ful of well rotted manure, horse poo is very good if you can find it and its' well rotted, I use chicken manure because I'm a city dweller, it's cheap and very easy to find.
Or I use Orchard Supply Rose Soil , because it already has alfalfa, bone and blood meal and other good stuff already in one bag, with a shovelful of my home made compost made from veggies and fruit scraps and grass.

I hope this information is of some use to you.
I also hope someone can give you a recipe, with quantities because I lost mine when I moved.
If I didn't have a back injury I would mulch every autumn with a blend of my home made veg-fruit-grass and horse manure compost. When I volunteered at vintagegardens I saw them putting a deep layer of rotted horse manure around the rosebushes in the Autumn, (4" or more, beneath the canopy every where up to 4" or so from the canes, you don't want it touching the canes. The horse manure broke down in the winter rains and fed the rosebushes the following spring and summer. His amazing collection of rosebushes affirmed the benefits of horse manure. I used bagged cow manure once and it left a horrid rainbow oil slick in my garden that smelt foul. I wondered what the h--- they were feeding those poor bovines. That is why I switched to bagged organic chicken manure.
Lux
Be careful to not over-fertilize, it will burn the plant and can kill a rosebush,
especially in a dry climate such as ours. I always water thoroughly the day before I fertilize.

In our VERY alkaline conditions, I've had good results with soil sulfur -- so you might try that. But I bet you've already learned that Teas and Chinas will tolerate more alkalinity than many other roses.

Teas & Chinas thrive in TX, but the alkaline soils do need improvement.

I'm new to gardening in caliche, too. Main emphasis seems to be, acidify the soil by constantly adding pine bark, oak leaves, sulfur, etc. The soil can have all of the iron, phos., & nitrogen a plant needs, but until the soil is the proper pH, it's unavailable to plants. Horse manure & alfalfa (in moderation) have worked well, too.

I've been digging (chopping out, actually) large planting holes & planting with at least 1/3 pine fines mixed in the replacement soil. A raised bed of improved soil would be even better.

I was recently looking up how to fertilize our blackberries & peaches & was surprised to learn that balanced fertilizers aren't particularly recommended here, as calcareous alkaline soils tend to tie up & accumulate too much phosphorous. The recommendation was for pure ammonium sulfate, to provide nitrogen & acidify the soil enough to make phos., iron, & other nutrients, that are generally in place, available to the plants. You can sure kill a plant fast with too much, though, & long-term, I prefer building real soil, with organics.

Another surprise was that plants can also be deficient in calcium. With all this caliche & limestone, you'd never think so, but the calcium carbonate of caliche isn't a usable form to plants.

So...soil test, replace caliche or build raised beds of improved soil & add organic acidic amendments like pine mulch & oak leaves on a regular basis. I just cautiously threw some sulfur around some plants today. Used to use it a lot on alkaline black gumbo, but this area gets much less rainfall, so I'm trying not to burn up my plants.

Cheers
Tricia

Just a comment regarding the numbers in fertilizers. 5-5-5 is exactly the same as 20-20-20 with regards to the primary macronutrient balance the only real difference being how much one needs to apply to supply a particular quantity of a required macronutrient to the soil. Whether and how much of this macronutrient will be made available to the plant and how fast, will depend on the source of the nutrient, the delivery method, the fertilizer's mechanical properties, the weather, irrigation, and of course the soil properties. Also, there are secondary macronutrients like Magnesium, Calcium and Sulphur and a host of micronutrients that might need to be provided or might need NOT to be provided. In this respect two composite 20-20-20s may be very different between them.
Nik

Good luck.. Do post some pictures when you get a chance.

It is actually unusual for soil that has not been used for agriculture to be deficient in phosphorous. Nitrogen moves through the soil and can deplete rapidly, but phosphorus stays put. Too much phosphorus can be damaging to plants. "According to the University of South Florida IFAS Extension, phosphorus will accumulate to toxic levels when applied as often as nitrogen and potassium." This means that continued use of a "balanced" fertilizer (like a 5-5-5) can lead to over accumulation of P!

I have horses and the main thing I do for my roses is apply compost of horse manure/stall leavings a few times a year. I have used horse manure of any age--well composted, somewhat composted, straight off the pitch fork from cleaning stalls--with only good results. I do keep it from actually touching the canes at the base of the plant.

Since I'm trying to be aware of my already good phosphorus levels, and the compost is adding more NPK plus a host of other goodies for the soil the only thing I add is nitrogen by way of alfalfa pellets because we know that's what depletes the most rapidly.

I also garden in what's normally heavy compacted clay, but with the generous compost amendments it's pretty wonderful stuff. I'm a feed the soil not the plant type gardener. Personally, I think overall soil health which makes the nutrients *available* is as important as what nutrients are there in what quantities.