I got these tips in email, without any attribution. These seemed interesting, so am posting them here; if you have further feedback or more tips, please let me know through comments.
Fish Emulsion (5-0-0) is incapable of damaging roses even if you use too much. If you have a fisherman in the family or as a neighbor? You could safely add 1 or 2 fish heads to each rosebush per year, buried 6 inches deep below dripline.
Epsom salts (Magnesium sulfate) help roses to have good basal growth. Use after soil has warmed, frost is over. 2-3 oz per established tender roses, up to 1/2 cup per hardy shrubs.
Banana Skins: Tomatoes as well as roses love bananas…buried just below surface of soil they provide potassium, calcium, magnesium, sulfur, phosphate, sodium and silica, all of them useful stuff.
Alfalfa: Meal (2 cups) pellets (1 cup) per plant gives N, Ca, Mg, Cu, Zn, P, K, Fe, Mn and Boron. If you have rabbits – use their pellets to enrich soil.
Egg shells: Crushed eggs shells…Lilacs and Tomatoes love calcium….During the fall and winter my crushed egg shells go to my lilacs and during the vegetable growing months they are carried out to my vegetable garden and scattered around the base of my tomato plants.
Coffee For Your Flowers: After your morning coffee, remove the filter and grounds and set them aside to dry. When the grounds are thoroughly dried, scatter them around the garden as an organic plant food. Don’t use too much in one area because coffee grounds tend to raise the acidity of the soil. Use the filter to line the bottom of flowerpots to keep the soil from falling through the drainage holes. I have used them for my rhododendrons, evergreens and some to my roses.
Mulch: Add organic matter to soil- Hay or leaves, straw, or corn cobs ground up, pulverized tree bark, old or rotten sawdust. Add 3″ deep mulch by first of June if summer warm.
There are 25 different rose scents. The healthier your rose is, the more fragrant it will be. As a rule, darker colored roses have more fragrance than lighter ones except that the more petals a rose has the stronger the scent. Heavy petals with velvety sheen are more fragrant than thin ones. There is a connection between color and scent. Red and pink have typical rose scent, Yellow and white have scents of lemon, violet, nasturtium, Orange colored-fruity or clove scents. Some of the most fragrant varieties-Angel Face, Sunsprite, French Lace, Tiffany, Double Delight, Tropicana and Puppy Love.