Why You Should Fertilize Roses in August

• Aug 08, 2025
• by Julia Stygar

August marks a transitional period in the gardening calendar, especially for rose enthusiasts. By this point in the growing season, roses have typically undergone several growth cycles and may have already produced a few flushes of blooms. As summer begins to wane, many gardeners consider August the ideal time for a final fertilization before allowing roses to slow down and prepare for the coming dormancy of fall and winter. Here's why August is a smart time to apply that last round of nutrients.

1. Supports Final Bloom and Plant Strengthening

Roses are heavy feeders. After blooming through spring and early summer, they can become depleted of vital nutrients. A final feeding in August provides the nutrients needed for one last flush of blooms while also helping to strengthen the canes and root system. This is particularly important for climates where roses might continue blooming into September or even early October.

Using a balanced or slightly lower-nitrogen fertilizer—like a 5-10-10 mix—can encourage blooms and root development without promoting excessive leafy growth, which could be vulnerable to early frosts. This helps roses transition more naturally into their late-season growth phase.

2. Prepares the Rose for Dormancy

August fertilization is not just about current performance—it's also about future survival. As the days begin to shorten and temperatures start to drop, roses begin to prepare for dormancy. The nutrients provided in August help the plant harden off and store energy in its roots. Phosphorus and potassium are especially important for this process. These nutrients aid in strengthening root systems, improving disease resistance, and increasing the rose’s ability to endure winter stress.

By feeding in August and then stopping, gardeners signal to the rose that the active growing season is coming to an end. Continuing to fertilize too late into the fall, however, can stimulate new, tender growth that is likely to be damaged by the first frosts.

3. Timing Matters for Winterizing

Timing is everything when it comes to fertilizing roses late in the season. August is typically early enough to allow 6 to 8 weeks of time before the first expected frost in many temperate climates. This window gives the plant time to utilize the nutrients, harden off any new growth, and begin preparing for colder weather without pushing out vulnerable new shoots.

This strategy is particularly important for hybrid teas, floribundas, and other repeat-blooming varieties that may continue growing well into autumn if encouraged. By feeding in August, you're providing support for a final performance while also being mindful of the plant's need to wind down.

4. Best Practices for August Fertilization

For best results, choose a slow-release or organic fertilizer. Products such as composted manure, fish emulsion, or rose-specific organic blends can offer a gentler nutrient boost without the risk of over-fertilizing. Always water well before and after fertilizing to prevent root burn and to help the nutrients soak in thoroughly.

Pruning dead blooms and tidying up the bush can also help channel energy into healthy growth and root development.

In Conclusion...

In summary, August is a strategic time to apply the last round of fertilizer to your roses. It supports a final flush of blooms, fortifies the plant for winter, and aligns with the natural rhythm of rose growth. Thoughtful fertilization at this stage ensures that your roses are strong by the end of the season and ready for blooming in the spring.