I'm moving into a house with a dozen or so rose bushes in the front yard. I have no experience tending roses, though I have some general gardening knowledge. These roses were obviously someone's pride and joy at one time, but they've been neglected for a year or so while the house was empty. To varying degrees, they are now riddled with black spot. I'm in the foothills of the Sierras in California, northeast of Sacramento, so expecting a long hot dry summer. The roses are in mostly full sun. I'm wondering if the best approach right now is to prune the roses way back and let them recover for next year. Any advice is much appreciated.

Before you do anything, I'd get rid of what appears to be gravel under and around the roses as that, along with the brick wall behind them and the house walls and the concrete in front of them absorb, trap and radiate heat which literally cooks them for hours daily. No matter how much water you give them, that will cook it all out and cause great water stress. You can literally force even highly disease resistant types to contract diseases by severely water stressing them. You would be significantly better off removing the stones and planting something shallow rooted like alyssum under them and keep them watered well. I realize you may have restrictions against using organic mulches near your house as that is one of the newer fire proofing measures being instituted in many areas, but anything you can do to insulate the soil around their bases to reduce the soil temperature and retain moisture is going to seriously help. Mulching or at least planting low growing, shallow rooted annuals under them will go along way to rejuvenating them and recovering their health and productivity. I would not fertilize them until the heat remediation is completed and they are producing new growth. Nor would I prune them until then as right now, the remaining foliage is protecting the canes from more severe sun scald which can induce attacks by Flat Head Apple Borers which can literally kill the plants. They need rescuing from being cooked first, then once they are recovering and putting out more growth, you can attend to feeding and clean up of dead growth and perhaps a light prune to encourage them to look the way you want. If you have any doubt about the increased heat due to the passive solar collection surfaces where they grow, move around the area then step into where they stand and notice the increased heat that air contains. You can't do much to reduce that reflected, radiated heat but you can reduce the heat to the roots, which will then encourage the plants to fill out and grow fuller which will, in turn, begin shading more of the brick and house walls, further reducing the heat in the area. Good luck and congratulations!

I would include - when you remove the gravel, don't dig deeply into the soil as that can break the root stock roots, resulting in probable forests of Dr. Huey, the stock they are most likely budded on. Huey is IMMORTAL and any broken roots can often produce huge, vigorous plants of the stock. That's one thing that makes it such a great root stock for commercial production. As a garden plant, it's not highly desirable, but for roots upon which to grow other types, it's one of the best for the West.

Second, I wouldn't fertilize nor spray anything yet because fertilizers are the salt forms of the nutrients. Salts are the only form of nitrogen, potassium and phosphorus and all other trace elements the roots can absorb. When you water a water stressed plant with salty water, it pulls the less salty water from the plant and replaces it with the saltier fertilizer water. If too much saltier water is brought into the plant, that's what is called "burning" it due to too much salt. They need some time of being appropriately watered to recover from the stress they've been under before hitting them with fertilizer.

Lastly, fungicides can easily burn foliage in hot, direct sun. Any type of oil (neem, horticultural oil, etc.) sprayed on the foliage is sure to burn in that direct sun with the reflected, radiated heat. I think you'll find the roses will probably be quite healthy once you provide the soil insulation and begin watering them well. That lush new growth should be free from most issues once they've recovered. That's the sun part! Again, congratulations and good luck!

#1, get rid of that gravel under the bush's. Then take each bush at a time. Look it over. Cut out all the twiggy growth in the lower part of the bush. Cut out any dead wood. Then cut each cane down by 1/2. Don't do a hard prune. Water good a day before pruning. Then after you are finished pruning, Give each bush a wash and watering. If you can find Pine Bark Nuggets for your new mulch. Great mulch for roses. I use a lot of Espoma Rose Tone in my garden. One cup per bush every month. After applying, water it in good. You'll have roses in about 5 to 6 weeks. Don't forget to water good at least once a week. Twice is good. Water is the life blood of your roses.

Take a leaf blower and blow ALL the dropped leaves away, far away, then douse each rose heavily with a Bio-fungicide.
It will not make the current leaves on the plant look better but it will kill the black spot and stop further infections.
By douse , I mean gallons of treatment, not ounces.
Repeat, at least once a month till new leaves are full again.