Illinois, United States

Gypsum helps with root-growth. Sulfate of potash helps to induce blooms. All my 160 roses are own-roots, except for 4 roses which are grafted-on-Dr.Huey. I don't spray. In my heavy clay, pH 7.7, roses are healthy if I dig deep with a 5 feet trench shovel for drainage, and fix my pH 9 tap water with sulfate of potash and gypsum.

I'm in NW of Chicago, zone 5, 38 inch of annual rain plus 7 rain-barrels. Hot & humid summer with rock-hard clay high in magnesium. Austin and French Meilland like my heavy clay. In contrast, Albas, damasks, hybrid perpetual, and esp. Rugosas & hybrid Musk prefer sandy and loamy soil & need good drainage. Multiflora prefers high-rain & acidic loamy soil, but wichurana (Dr. Huey) prefers dry & alkaline.

For OWN-ROOT roses: PALE LEAVES prefer loamy soil & acidic rain. DARK-GREEN LEAVES like Intrigue prefer heavy/dense alkaline clay or alkaline-tap-water (pH 9 here).

GLOSSY LEAVES like Pat Austin and Twilight Zone: best with partial shade & wet & need alkaline minerals after heavy rain.

TINY LEAVES like William Morris prefer loamy & light and fluffy soil. LARGE LEAVES like Princesse Charlene de Monaco = vigorous & thick root that can handle clay

THICK LEAVES like Dee-lish and Double-Delight = heat tolerant.
5-leaflet = modern roses, OK with alkaline tap-water.
7-leaflet or thornless or blue-color = derived multiflora & need cooler sites & loamy & high-rain.
7-leaflet and many prickles = drought-tolerant & derived from species rose. Rugosa: prefer loamy/sandy & slightly acidic

Over-fertilization: wilting, leaves curl down.
Too acidic: leaves curl up & thinner, and blackspots, crisp burn on tips.
Too alkaline: Pale, leaves twisted (boron def) or crinkled (copper def).
Potassium def: zero blooms, balling, thin & weak stems, and blackspots.
Calcium def: less petals, stunt growth & tip die-back & pale and small upper leaves
Nitrogen def: small leaves & pale LOWEST leaves
Sulfur def: entire plant is pale & stunt growth
Iron def: pale UPPER leaves with greener veins

https://www.houzz.com/discussions/4346048/roses-that-perform-well-on-own-roots#n=129
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https://www.houzz.com/discussions/5971487/calling-strawchicago-re-clay-alkaline-soil-amendments-fertilizers#25991363
https://www.houzz.com/discussions/3241444/taking-care-of-plants-in-flood-drought-heat-and-cold#n=34
https://www.houzz.com/discussions/5993773/random-qs-observations-about-growing-healthy-roses#n=56
https://www.houzz.com/discussions/3954615/mineral-deficiency-symptoms-in-roses#n=76

Experienced (37 years)

Last visit: Tuesday, October 22nd