When and How to Fertilize Roses in Spring: 5 Expert Tips

When it comes to roses, one thing is for certain. To have healthy, floriferous plants, you need to feed them. Roses are heavy feeders that require a steady supply of nutrients to sustain them throughout the growing season. If you want them to thrive, fertilizer is a vital piece of the puzzle. 

Fertilizer is important for healthy growth and bountiful blooming, but that’s not the only reason to feed your roses. These precious perennials are vulnerable to several pests and diseases. A strong, healthy, well-nourished plant has a better chance of not only surviving an attack but of recovering in time for more flowers. 

Not all roses are the same, so different types may need a different fertilizing routine. The species matters less than the blooming habit, with repeat bloomers benefiting from more frequent feeding. Let’s walk through the process of caring for your newly planted rose, and then discuss continued care based on its blooming habit. 

Newly Planted Roses

For newly planted roses, and those that you haven’t planted quite yet, need their own specific feeding routine. In general, young roses need less fertilizer than their established counterparts. While they are heavy feeders, you can easily overwhelm a young rose with a routine that would work well for a mature one. 

Beginning at planting time, your rose will need a strong start if you want it to establish roots and settle into its new environment securely. However, too much fertilizer can burn the roots and cause your endeavor to fail. When it comes to feeding young plants, more isn’t always better. In fact, it’s quite the opposite. 

At Planting Time

You want to get off to a strong start, but there is a fine line between providing too many and not enough nutrients. Your soil plays a significant role in the beginning, and it’s always a good idea to conduct a soil test to see what, if anything, you need to add or balance. 

Roses like rich soil with a slightly acidic pH and plenty of organic matter. Fortunately, these two things go hand in hand, so when you add that organic matter, the pH will naturally go down. 

When you dig your hole, dig it two to three times the width of your root ball and work some well-rotted compost or manure in with the soil. You can also add a handful of slow-release fertilizer. A bit of bone meal at planting time will help with strong root development. 

First Season Care

After you get it in the ground, hold off for a bit. Make sure you water regularly and deeply. You want the water to go deep, sending the roots downward, firmly anchoring your shrub. 

For the first month, don’t fertilize at all. You want those roots to have time to anchor before the top begins to put on growth. During this time, just focus on watering. Don’t allow it to stay wet, though. The rule is to water deeply, not frequently. 

When your shrub begins to grow, after about a month, then it’s time to feed. Since your rose is young and vulnerable, it’s important to avoid giving too many nutrients at one time. You don’t want to burn those roots. 

Starting at about the one-month mark, give your plant an application of a mild fertilizer. Fish emulsion is great for this purpose. Another option is to use a gentle, slow-release formula or a liquid product diluted to half strength. 

Repeat this about every three to four weeks throughout the first spring and summer. Stop fertilizing about six to eight weeks before your average first frost date in the fall. This will prevent rapid growth before the cold weather. New wood is more vulnerable to cold. 

Established Repeat Blooming Roses

Once you’ve made it through the first year and overwintered, you’re ready to begin a more regular fertilizing schedule. From here, the important factor to determine is whether your plant is a once-blooming cultivar or a repeat-bloomer. 

Most Old Garden varieties and certain climbers and ramblers only flower once, in the spring. Most modern varieties are repeat bloomers, so naturally, they will benefit from more fertilizing. 

Start Early

Your first application will depend on your climate. The farther south you go, the earlier you’ll want to get started. In cooler climates, you’ll naturally hold off longer. 

Fertilizing too early in the spring can cause root burn. If the plant is not actively growing yet, you can end up with salt burn on the roots, which can lead to nutrient toxicity and possibly death. The stress of over-fertilizing can make it more vulnerable to pest and disease damage. 

Wait until the plant reenters a growth period to apply your first treatment. Once you see a few inches of new growth, it’s time. 

Choose Your Formula With Care

Your first application should be a high-nitrogen formula. Nitrogen is responsible for green growth, so this extra boost of the nutrient will accelerate the top growth of your rose, preparing it for a big bloom. 

For this initial application, select a formula with a higher nitrogen concentration. Then top dress with alfalfa meal, a gentle fertilizer with a high nitrogen-to-phosphorus ratio. You need both phosphorus and nitrogen to promote healthy leaves and blooms.

Going forward, after the first application, switch to a balanced formula.  A formula of 10-10-10 is appropriate. For your second application, you can use a bloom booster or one that is slightly higher in phosphorus and potassium. 

Spread the Love

When applying your fertilizer, be generous with the area you cover. While you don’t want to overdo it, ensure that you spread it evenly around the base, all the way to the drip line. This will change based on the age of the plant. 

The drip line is the outer edge of the canopy. Think about where the water would drip off when it’s raining. Typically, this is how far the roots extend, so you want to deliver fertilizer to the entire root system. Consider where the canopy extended to the previous year.

Water After Application

After you apply your fertilizer, be sure to water your plant thoroughly. Watering activates the fertilizer, dissolving granules and pushing it down into the root system, distributing the nutrients more evenly. 

Water also dilutes the fertilizer, so that it doesn’t deliver too much to one area of the roots and burn them. This is primarily true with granular formulas. If you use a liquid formula, hold off on watering for a few hours.

Repeat at the Right Intervals

Repeat-blooming roses need a steady supply of fertilizer throughout the summer if you want them to flower more than once. While some of them might produce a few flowers without ample nutrients, they aren’t likely to have another big bloom. 

Fertilize immediately after the first flush, at the same time that you deadhead the plant. This will help to replenish what’s lost and set the stage for the second flush. From here on, repeat every two to three weeks, using your balanced formula.

At the end of the summer, transition to a fertilizer with a low nitrogen and high phosphorus ratio. This will promote root growth, preparing for the dormant season. 

Since nitrogen encourages green growth, avoid applying much at all after about mid-summer. That new growth is tender and makes the shrub more vulnerable to cold damage. 

As with your first-year plants, stop altogether about six to eight weeks before your first frost. This will help ease your rose into dormancy in time for those freezing temperatures. 

Established Once Bloomers

Roses that only bloom once per year won’t need quite as much fertilizer, as they won’t be putting as much energy into producing flowers. That’s not to say they won’t benefit from more frequent application; it’s just that it’s not necessary for blooming.

For these plants, which include those Old Garden roses, some climbers and ramblers, Carolinas, Damasks, and Albas, that spring application is the most vital. These plants predominantly bloom in late spring.

Your first and primary application of fertilizer for these once bloomers should happen at the same time as it would for repeat bloomers. In early spring, once you see a few inches of new growth, you can be sure that your plant will utilize the nutrients, and they won’t harm the roots.