There are a few possible reasons why your roses may be turning pink instead of the expected red color. The most common causes are related to soil pH, insufficient sunlight, and certain rose varieties that naturally produce pink blooms. With some adjustments to your rose care regimen, you can often get those pink roses turning red again.
Check the Soil pH
One of the most common reasons for pink roses is an unsuitable soil pH. Roses prefer a slightly acidic soil in the 6.0-6.5 pH range. If the soil pH creeps above 7.0 into alkaline territory, it can interfere with the plant’s uptake of iron. Iron is essential for encouraging the formation of anthocyanins, which are the pigments that give roses their rich red color. Without adequate iron, those pigments can’t develop properly and you end up with lighter pink blooms.
Testing your rose bed soil pH is quick and easy. Pick up an inexpensive soil testing kit at a garden center or hardware store. Follow the directions to mix a soil sample with the test solution and determine the pH. If the reading indicates an alkaline pH level, you can amend the soil with aluminum sulfate or elemental sulfur to help lower and acidify the pH. Re-test in a few weeks and continue adding sulfur until you reach the ideal slightly acidic range for roses.
Provide Enough Sunlight
Along with soil pH, exposure to sunlight is critical for developing red rose pigments. Roses need a minimum of 6 hours of direct sun each day to produce their best flowers. Anything less can result in lighter and fewer blooms.
If your rose bushes are located in too much shade, such as the north side of a building or behind tall plants or structures, try to prune or remove any foliage or branches blocking the sunlight. You may need to relocate the roses altogether to a spot with better sun exposure if that’s an option. Morning sun in particular helps encourage pigment production.
| Hours of Sunlight | Rose Color |
|---|---|
| Less than 4 hours | Mostly white or very light pink |
| 4-6 hours | Light pink |
| 6 or more hours | Vibrant red |
Pick Red Varieties
Some rose varieties are genetically predisposed to producing pink blooms regardless of sun and soil conditions. Check the label or description of the rose types you purchased. If they are classified as pink rose cultivars, they won’t ever reach the deep red hues of a classic red rose.
For reliably red roses, look for cultivars labeled as red or classified as having a warm, orange-red color. Good choices include ‘Mister Lincoln’, ‘Veterans Honor’, ‘Chrysler Imperial’, and ‘Black Baccara’. Ask for assistance at your local nursery to pick red rose types that will grow well in your specific climate and conditions.
Allow Time to Mature
Young rose bushes that are still becoming established often produce lighter pink blooms at first. As the plant matures over a couple seasons, the blooms typically darken to a rich red color. Have patience with young plantings and allow them time to grow and develop deeper hues.
Continue caring for the roses properly by watering 1-2 inches per week, fertilizing monthly, and pruning back each winter. With age should come deeper flower colors.
Use Acidic Fertilizer
While soil pH is certainly the major factor influencing rose color, the pH of your fertilizer can also play a role. Fertilizers with a neutral or slightly alkaline pH (above 7.0) won’t help roses achieve red blooms. Instead, look for fertilizers specially formulated for roses with an acidic pH around 5.5-6.0. These acidifying formulas help keep soil pH in the ideal range while providing roses with the nutrients they need.
Avoid Over-Pruning
Heavy pruning that removes too much of the rose bush can reduce blooms and result in weaker color the following season. Aim to prune up to one-third of the plant’s height, removing any dead or damaged canes. Make cuts just above outward facing buds. Over-pruning causes excessive stress on the plant that shows up as fewer and lighter colored blooms until it recovers.
Protect from Cold
If winter temperatures drop below freezing where you live, be sure to protect rose bushes from cold injury. Damaged or desiccated canes from cold exposure will produce weaker blooms the next season. Mound mulch, leaves, straw or other insulating material around the base of each bush. In very cold climates, wrap bushes with burlap or rose cones for added protection.
Summary
Pink roses aren’t necessarily cause for concern, as long as that pale color is expected for that variety. But for roses that should be turning out rich, red blooms, take a look at soil pH, sunlight, maturity, fertilizer, pruning, and cold protection to help achieve the right color. With a few tweaks to your rose care regimen, you should see those pink blooms transition to deep crimson red.
