Best Rose Fertilizer (10-20-15): High Phosphorus for Maximum Blooms, Vibrant Color & Strong Canes Buy on Old Cobblers Farm
Old Cobblers Farm™ Wicked Growth Roses Fertilizer
by Wicked Growth — 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 |
| Derived From | Urea, Diammonium Phosphate, Muriate of Potash, Silicon Dioxide |
| Item Form | Granular |
| Release Speed | Moderate-release |
| Application Rate | ½–2 cups / plant (by size) |
| Method | Side-dress at drip line |
| Frequency | Every 4–6 weeks during bloom season |
| Sizes | 5 lb | 10 lb | 15 lb | 20 lb |
| Supports | Hybrid tea, floribunda, grandiflora, climbing, shrub, miniature, knockout, David Austin, all rose types |
| Setups | Rose beds, borders, containers, trellises, cutting gardens |
| Feature | Old Cobblers Farm™ Wicked Growth Roses Fertilizer | 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| NPK | 10-20-15 | 4-3-2002 | 18-24-16 | 6-9-2006 | 12-6-10 | 12-6-10 | 4-6-2002 | 8-12-2004 | 2000-10-10 | 12-4-2008 | 2-8-2004 |
| Phosphorus | 20.0% | 3.0% | 24.0% | 9.0% | 6.0% | 6.0% | 6.0% | 12.0% | 10.0% | 4.0% | 8.0% |
| Potassium | 15.0% | 2.0% | 16.0% | 6.0% | 10.0% | 10.0% | 2.0% | 4.0% | 10.0% | 8.0% | 4.0% |
| Form | Granular | ||||||||||
| Sizes | 5 lb | 10 lb | 15 lb | 20 lb | 4 lb, 18 lb | 1.5 lb | 4 lb | 3.5 lb | 4 lb | 4 lb | 50 count | 32 oz | 4.5 lb | 32 oz |
| Release Speed | Moderate-release |
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.
