How To Grow And Care For Osiria Roses (Hybrid Tea Rose)

You might see them on Valentine's Day—the Osiria rose (Rosa 'Osiria') is unmistakable, even amongst its fellow red-hued peers. Though it possesses the same shape as the other standard grocery store varieties, the one thing you can't miss about the Osiria rose is the two-tone, striking red and white petals with a gentle ombre. It's anything but generic.

If you're considering a new addition to your garden, consider the Osiria rose, a hybrid tea rose that produces velvety, voluptuous blooms in the late summer and fall. Their dual-toned petals, which begin as a bright cherry red, will gently taper into a calmer shade as the season progresses. With its striking petals, the Osiria rose is the flower your garden' needs for that coveted wow factor, given that it can produce florist-worthy (and florist-sized) blooms.

Plant Attributes

Osiria Rose Care

The Osiria rose grows in various climates. When adding one to your garden, start with good soil that drains well. With this rose, things can develop slowly, so don't get discouraged. It can take up to five years for the Osiria rose bush to achieve its peak size (three to four feet tall). 

Though it's known to be challenging to cultivate, it will reward you well not only by its blooms but also by its irresistible scent. When planting, plenty of direct sunlight is ideal. More sun spells more flowers. However, you also want the location to protect from wind and rain—the heads will droop on weak stems. Some cultivars can be invasive in areas where they can spread.

Light

Osiria roses grow best in full sunlight, at least four hours daily. This flower will tolerate light shade, but the more sun it receives, the healthy the plant will be. Sunlight also helps produce bigger, showy blooms.

Soil

All roses prefer soil rich in organic matter. The hybrid tea rose prefers nutrient-rich, acidic soil that's well-draining and loamy. The Osiria rose can grow in many soils, but you risk root rot and fungal infections if the water can't drain. Add mulch to the ground in the spring after the last frost. Mulching to the roots helps conserve water and protect the plants in warmer weather when the leaf buds begin.

Water

The Osiria rose water requirements vary depending on temperature and soil conditions. On average, one to two inches of water every week is enough for the hybrid tea rose. More frequent watering will help sustain the flower in areas where the soil is sandier, and the temperatures are higher. When it is time to water, you will know because the top few inches of soil are dry. Avoid watering the foliage and instead focus on the roots. Deep watering builds strong roots and helps during warmer temperatures.

Temperature and Humidity

Hybrid tea roses are relatively cold-tolerant when sold as bare-root plants. These plants will go dormant in late winter or early spring. Most rose varieties bloom best in warm, humid conditions, at least 80°F.

Fertilizer

Osiria roses benefit from regular fertilization. After the last frost and before new growth, start fertilizing plants every week or every other week. Fertilizers designed for roses typically include nitrogen, phosphorus, and potassium. Adding nutrients like iron and magnesium sulfate can help produce healthier plants depending on the soil. Iron reduces yellowing leaves, and magnesium sulfate helps produce showy blooms. Stop fertilizing about six weeks before the expected first frost to stop new growth and encourage dormancy.

Types of Osiria Roses

Osiria roses have several cultivar varieties. Each cultivar highlights unique colors, fragrances, and petals. Home gardeners enjoy the wide variety:

• 'Peace': This hybrid tea rose has primrose-yellow petals that fade to shades of soft rose-pink in six-inch blooms. The intense fragrance is winter-hardy and diseases resistant.
• 'Midas Touch': A golden-colored flower with four-inch blooms. These blooms contrast beautifully against dark green foliage and have a fragrant musk scent.
• 'Mister Lincoln': A classic, red beauty. This hybrid tea rose has a long stem, double petals, and four-inch blooms.
  

Pruning

As for pruning, it's acceptable and encouraged to deadhead. This pruning clears the way for new flowers, and experts recommend cutting anywhere from a fourth to half an inch from a five-petal, outward-facing leaf. Make these cuts at an angle, around 45 degrees, to help water drain from the ends.

Pruning the Osiria rose is similar to other roses, meaning if you regularly maintain the plants, less pruning is necessary. Prune before new growth emerges in the spring. Remove the dead, diseased, or damaged canes to encourage new growth. If the branches are more substantial and healthy, prune only a third of the stem's length.

Propagating Osiria Roses

There are several ways to propagate roses. Cuttings, air layering, or budding can propagate the Osiria rose. Several cultivar varieties are patented, so always check the propagation guidelines before growing from seed or propagation. Budding is an easy way to create more Osiria roses using the parent plant's buds. Here's how to propagate the Osiria rose by budding: 

1. Look for rose buds attached to a strong rose cane while the weather is still warm. 
2. Using pruning shears or a sharp, clean knife, cut below the fourth set of leaves (remove all the leaves but the top group) at a 45-degree angle so the water can efficiently drain from the stem. Place stems in water.
3. Dip the cuttings into a rooting hormone (if desired) to help aid the growing process.
4. Fill a peat pot with a soil mixture containing vermiculite. Make sure to water the soil mixture.
5. Use your fingers or a pencil to create a small hole in the soil mixture, about two inches deep. 
6. Add twigs, around eight inches long, to the perimeter of the container. 
7. Fill a plastic bottle or cup with a peat moss mixture or potting soil. Make small holes in the bottom to allow draining. 
8. Place the peat pot, including the rose cutting, into the plastic bottle or cup. 
9. Cover the rose cuttings with a plastic bag or large jar to generate humidity. Make sure not to touch the leaves when covering the rose cuttings. 
10. Place the entire system in an area with indirect sunlight. Make sure the soil is moist but well-draining.
11. New growth should emerge within four to six weeks. 

How to Grow Osiria Roses From Seed

Growing an Osiria rose from seeds is challenging, and the results vary depending on the cultivar strand and environmental conditions. 

1. Start by collecting seeds, either from a garden center or an existing plant, after rose hips begin to dry out—Don't wait until they are dehydrated because it is likely that the seed is dead. 
2. Use a sharp, clean knife to cut open the seeds. After, remove any excess debris or pulp from the seeds by gently wiping them or using a colander. 
3. Begin seed germination by soaking them in water (at least an hour). A diluted hydrogen peroxide solution can help prevent mold from growing on the seeds. 
4. After removing the seeds, place them on a damp paper towel and cover them with a second wet towel. Keep the covered seeds in a cold refrigerator for a few weeks. You can place the damp towels in a plastic bag for convenience. 
5. While refrigerated, make sure the paper towels remain moist. Remove the seeds from the refrigerator in early spring—Seeds should begin to sprout within two to three weeks if left in a warm environment or planted in a seed starting tray. 
6. Cover the seeds with potting soil and keep the tray in a warm, moist environment. 
7. After the first two leaves are visible, transplant the seedlings to their final location after the last frost passes. Add fertilizer to help plants grow. 

Overwintering

The Osiria rose is relatively cold-hardy depending on the environment when meeting certain conditions. The soil must remain moist, and pruning will help protect the plant's roots during the colder weather. Prune away any diseased, infected leaves and move them away from the plant so it does not impact the soil. Mulching the roots and canes will add an extra layer of protection from the cold weather and help promote growth the following season. 

This process includes protecting the plant's graft union at or below the soil level near the rootstock—use at least six to eight inches of soil over the plant to provide protection. Remove this additional soil after the last frost and before new growth emerges in the spring. Pruning the canes is another way to protect the plant by reducing the energy needed to preserve longer branches. 

Common Pests & Plant Diseases

The Osiria rose, like any other plant, is at risk for pests and disease. Powdery mildew, black spot, and rose rust are some diseases to be aware of, monitor, and treat. Maintain proper water drainage and sunlight requirements to help prevent infections from forming.

Pests that cause trouble for the Osiria roses include spider mites, aphids, caterpillars, sawflies, and leafhoppers. Rabbits and deer are known to eat these flowers. If plagued by a pest infestation, use insecticidal soap as directed until resolved.

How to Get Osiria Roses to Bloom

Maintain adequate sunlight and soil health to encourage blooms. Deadheading flowers after the final bloom will help protect the plant for the following season, and removing spent flowers during the season will promote continuous growth. To increase blooms within a season, fertilizing the plant throughout the year (at least two or three times) will encourage larger, healthier blooms. Fertilization should occur in early spring, after pruning, and after the season's first bloom. Protecting the plant's root bulb during winter will help ensure healthy blooms.

Common Problems With Osiria Roses

Osiria roses show health decline when suffering from pests or diseases through discoloration, small holes in the leaves, and wilting or spent blooms. While generally disease resistant when proper sunlight, soil health, and watering are maintained, some issues can still occur.

Leaves Turning Yellow

Yellowing leaves typically indicate overwatering. When the soil does not drain properly, Osiria roses can begin to droop. Not enough sunlight and improper soil pH can also cause yellowing leaves. Black spot disease is present when overwatering continues and will be visible on the upper side of the leaves. If black spot disease is present, the lower leaves are usually impacted first and can fall off or spread if left untreated. Treat by removing diseased foliage and allowing the plant to dry by increasing its exposure to sunlight or transplanting it. After, apply a fungicidal spray for a few weeks to prevent the new spots from appearing.

Curling Leaves

Sawfly infestations can cause leaf curling in roses. Typically present in spring or early summer, sawfly eggs are introduced to rose leaflets and leave behind a chemical that initiates the leaf rolling. Fungal infections, such as powdery mildew, can also cause curling leaves. Before white spots appear on the leaves, rose foliage may curl, indicating that powdery mildew is present. Prevent fungus on plants by keeping them in an area with proper air circulation and watering them in the morning so the foliage can dry. Horticultural oils can also help to prevent the disease from spreading.