Here's When to Fertilize Roses for Bigger, Brighter Blossoms

Keep your plants healthy and help them produce plenty of flowers by knowing how and when to fertilize roses and by giving them the best rose fertilizer.

For the most part, roses are pretty tough plants that will grow and bloom without demanding much attention from you. But to enjoy the biggest blooms and healthiest growth, roses need more feeding than most flowering shrubs. Fortunately, providing the nutrients they need is easy, and you can do that organically or with synthetic fertilizer products. The key is to use the best rose fertilizer with the right balance of nutrients and to do so regularly. Knowing when to fertilize roses and keeping a consistent schedule will reward you with a garden filled with stunning, fragrant flowers.

'China Doll' pink roses
Richard Baer

The Best Rose Fertilizers

Like all plants, roses need three primary nutrients: Nitrogen (the "N" on a fertilizer label), phosphorus (P), and potassium (K), plus several secondary and trace elements. Trace elements (boron, chlorine, copper, and iron) promote plant cell and root growth. Most garden soils provide some of these nutrients, but they become depleted as the plants grow and use them. That's where you come in; adding nutrients back to the soil helps roses perform their best.

Primary nutrients are available from both organic (derived from plant or animal life) and synthetic or inorganic materials. Fertilizers come in dry, liquid, or foliar spray form. Shop for a product labeled for roses and carefully read the directions for amounts and frequency of application. Remember that more is not better; excessive fertilization can damage plants or make them susceptible to disease and insect attack.

Organic options, such as fish emulsion, manures, compost tea, and alfalfa pellets, are good choices and have the benefit of being less likely to overload the soil with unnecessary compounds. Commercial products that contain mixtures of organic nutrients are also available. The nutrient concentration in organic products is generally lower, so more frequent applications are recommended, but these products also feed soil organisms and develop humus (organic material, usually from decomposing leaves or other plants), making the soil healthier for plant growth.

How and When to Fertilize Roses

Most roses need regular feeding throughout the growing season. For newly-planted roses, add plenty of compost to the hole at planting time, and then provide a liquid fertilizer (synthetic or organic) about a month later, after they're established. Start feeding older plants in spring when new growth is about 6 inches long. Most will benefit from a second feeding of liquid fertilizer after the first bloom, and repeat-blooming roses do best with regular feeding every 2-3 weeks until late summer.

If conditions are dry, water your roses before feeding them, and keep them well hydrated afterward. This helps the plants absorb nutrients better and prevents fertilizer burn on roots and leaves. Stop feeding about eight weeks before your average first frost date to avoid stimulating too much new growth that cold temperatures will damage.

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