Best Rose Fertilizer (10-20-15): High Phosphorus for Maximum Blooms, Vibrant Color & Strong Canes Buy on Old Cobblers Farm
Roses are heavy feeders that demand more phosphorus than most garden plants. This 10-20-15 delivers double the P relative to nitrogen — fueling non-stop bloom production, intense petal color, and vigorous cane development all season long.
Old Cobblers Farm™ Wicked Growth Roses Fertilizer
by Conventional Fertilizer — Littleton, NH
20% Phosphorus for Maximum Blooms
Double the phosphorus of a balanced fertilizer. P drives flower bud formation, petal count, and continuous rebloom in hybrid teas, floribundas, and all repeat-blooming roses.
Intense Petal Color
Phosphorus fuels the pigment pathways that create deep reds, vibrant pinks, rich yellows, and saturated purples. More P = more vivid, show-quality blooms.
15% Potassium for Strong Canes
Potassium strengthens cell walls in canes and stems, improves winter hardiness, and enhances natural disease resistance against black spot and powdery mildew.
10% Nitrogen for Healthy Foliage
Enough nitrogen to maintain dark green, glossy foliage without pushing excessive vegetative growth that delays flowering or attracts pests.
6–22 Bushes Per Bag
At ½ cup for miniatures to 2 cups for large shrub roses, one 5 lb bag feeds 6–22 plants per application. Reapply every 4–6 weeks.
Season-Long Feeding Program
Start after spring pruning, feed every 4–6 weeks through summer, and stop 6 weeks before first frost. Simple, consistent schedule for maximum performance.
All Rose Types
Hybrid teas, floribundas, grandifloras, climbers, shrub roses, miniatures, Knockouts, David Austins — every rose variety benefits from this high-P formula.
Trusted by 20,000+ Growers
Developed in Littleton, New Hampshire. Sold nationwide on Amazon, Walmart, eBay, and theoldcobblersfarm.com.
| NPK Ratio | 10-20-15 |
| Item Form | Granular |
| Coverage | ~6–22 rose bushes per 5 lb bag |
| Category | Conventional Fertilizer |
| Type | Flower & Garden |
| Sizes | 5 lb | 10 lb | 15 lb | 20 lb |
| NPK | 10-20-15 |
| Nitrogen | 10% |
| Phosphorus | 20% available phosphate |
| Potassium | 15% soluble potash |
| Form | Granular |
| Rate | ½–2 cups / plant |
| Method | Side-dress at drip line |
| Frequency | Every 4–6 weeks |
| Sizes | 5, 10, 15, 20 lb bags |
| Best For | All rose types — hybrid tea, floribunda, climber, shrub, miniature |
| Feature | Old Cobblers Farm™ Wicked Growth Roses Fertilizer Old Cobblers Farm | Rose-Tone Organic Espoma | Water Soluble Rose Food Miracle-Gro | All-in-One Rose & Flower BioAdvanced | Rose Plant Food Vigoro | Rose Plant Food Expert Gardener | Total Advantage Rose/Flower Dr. Earth | Rose & Flower Spikes Jobe's | Morbloom (Fish based) Alaska | Shake 'n Feed Rose/Bloom Miracle-Gro | Tiger Bloom FoxFarm |
|---|---|---|---|---|---|---|---|---|---|---|---|
| NPK | 10-20-15 | 4-3-2 | 18-24-16 | 6-9-6 | 12-6-10 | 12-6-10 | 4-6-2 | 8-12-4 | 10-10-0 | 12-4-8 | 2-8-4 |
| Form | Granular | — | — | — | — | — | — | — | — | — | — |
| Coverage | ~6–22 rose bushes per 5 lb bag | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed |
| Price / Size | 5 lb | 10 lb | 15 lb | 20 lb | $8.99 | $8.28 | $21.96 | $10.97 | $5.97 | $12.99 | $10.99 | $9.98 | $20.97 | $22.50 |
| Our Take | The purpose-built rose formula with 20% phosphorus for maximum flow... | — | — | — | — | — | — | — | — | — | — |
Rose-Tone Organic
Water Soluble Rose Food
All-in-One Rose & Flower
Rose Plant Food
Rose Plant Food
Total Advantage Rose/Flower
Rose & Flower Spikes
Morbloom (Fish based)
Shake 'n Feed Rose/Bloom
Tiger Bloom
20% Phosphorus for Maximum Blooms
Double the phosphorus of a balanced fertilizer. P drives flower bud formation, petal count, and continuous rebloom in hybrid teas, floribundas, and all repeat-blooming roses.
Intense Petal Color
Phosphorus fuels the pigment pathways that create deep reds, vibrant pinks, rich yellows, and saturated purples. More P = more vivid, show-quality blooms.
15% Potassium for Strong Canes
Potassium strengthens cell walls in canes and stems, improves winter hardiness, and enhances natural disease resistance against black spot and powdery mildew.
10% Nitrogen for Healthy Foliage
Enough nitrogen to maintain dark green, glossy foliage without pushing excessive vegetative growth that delays flowering or attracts pests.
