Roses grow easily, produce colorful blooms, and have a sweet scent. However, it can be concerning when your rose garden starts to lose its vibrance. If the leaves are turning yellow, the stems are drying, and the flower buds are wilting, you might fear that your roses are dying, with no hope of coming back.
Here are 8 reasons why your roses aren’t coming back:
- Fungal disease
- Pest infestation
- Lack of nutrients
- Wrong growing conditions
- Poor pruning techniques
- Failure to mulch for winter
Rose gardens die for various reasons. I’ll discuss the reasons your roses are dying and why they might fail to come back.
1. Fungal Diseases
One of the primary reasons roses die is because of fungal diseases. Although some rose varieties are best suited for shaded areas, most need full sun. When exposed to moist conditions for too long, roses are attacked by fungal diseases that kill roses if not treated immediately.
Here are some fungal diseases that are deadly to roses:
- Rose black spot
- Powdery mildew
- Rose dieback
The chart below outlines each of these diseases and their unique characteristics. Below, I will explain the causes of each disease and provide some tips on managing them.
Rose Black Spot
As the name suggests, rose black spot is a fungal disease characterized by circular, black spots that are about ½-inch (1.27 cm) wide. The fungus Diplocarpon rosae is responsible for this attack on leaves. A yellow area usually surrounds the black spot.
The disease attacks a few leaves initially, but if left untreated, the entire rose plant will have black spots. Over time, the leaves will weaken, making the rose plant more vulnerable during the winter season.
During summer, the disease is dormant even if it’s present. Black spot is more active and harmful when humidity levels are high.
Black spot disease will kill your rose garden if you don’t take measures to treat or prevent it.
The measures you can take against black spot include:
Choose Black-Spot Resistant Varieties
The first thing you can do is plant rose varieties resistant to black spot. These include Grandiflora Roses (Candelabra and Queen Elizabeth), Floribunda Roses (Iceberg and Betty Prior), Hybrid Tea Roses (Mr. Lincoln, Dainty Bess, and Elizabeth Taylor), and Shrub Roses (Knockout, The Fairy, and Carefree Beauty).
Use Fungicide Sprays
You should use fungicide sprays, even on resistant rose flower varieties. Check the label to confirm that the spray fights black spots or fungal diseases in plants.
Remove Fallen & Infected Leaves
Remove all fallen leaves and mulch where infected leaves fall. Ensure you use fresh mulch when the rose starts getting new growth.
You should also remove infected leaves as soon as you see them, especially during the growing season. Remove the leaves from your garden completely. They can still affect your roses, and the disease will remain active if they are present.
Water Properly & Provide Adequate Sun
Avoid getting the leaves wet when watering. Instead of overhead irrigation, water the soil. If you prefer an irrigation system, go for drip irrigation.
Do your best to avoid watering your roses in the evening as well. The moisture can stay on the plant long enough to invite unwanted pests and pathogens. It’s best to water them in the morning, shortly before sunrise.
When planting your roses, choose a sunny spot so that the leaves will dry quickly if they get wet.
Regularly Inspect the Canes
Lastly, inspect the canes regularly and carefully. If canes have black spots, cut them at least 1-2 inches (2.54-5.08 cm) within the bud union.
Another disease that kills roses is powdery mildew caused by the fungus Podosphaera pannosa. Powdery mildew occurs when humidity is relatively high at night and low during the day. Roses planted in shaded areas are more vulnerable to powdery mildew.
The fungus that causes powdery mildew needs to live in the rose plant for 72-96 hours in favorable conditions before the powdery mildew attacks the plant. The fungal spores form a chain and attack the plant’s new cells. In the process, the fungus utilizes the plant’s moisture and nutrients.
As the mold grows, the rose plant becomes more deprived.
Powdery mildew destroys the plant as it takes over, not just because it alters the plant’s structure, but also because it deprives the roses of water and nutrients. In the long run, the plant will die and not come back.
The fungi thrive in the following conditions:
- In the springtime, when the days are warm and nights are cool
- When air circulation is poor
- When humidity is high
- On dry leaves
Compared to other fungal pathogens, the spores responsible for powdery mildew do not grow on wet leaves. This is why the disease doesn’t spread during the rainy season.
Signs and Symptoms
Powdery mildew affects different parts of the rose plant, including leaves, flowers, sepals, and unopened flower buds. This fungus affects roses at different stages of growth, but younger roses with more succulent tissues are attacked first.
The symptoms of powdery mildew include the following:
- Red blister-like spots on the upper leaf surface
- Grayish-white powdery substance on young leaves, shoots, and buds
- Drooping leaves
- The shape of the infected leaves may be distorted
- Flower buds fail to open
- Poor-quality flowers
- Stunted leaf growth
When the affected leaves change their shape, it affects the rose plant’s ability to photosynthesize food. This is the reason the rosebuds fail to open. If powdery mildew goes untreated, the leaves will start falling prematurely, the rose plant will stop producing flowers, and the plant will die over time.
Control and Prevention
Although powdery mildew can quickly kill a rose garden, you can control the spread if you catch the disease early on.
Here are tips on how to control and even prevent powdery mildew from attacking your rose garden:
- Remove any fallen leaves and debris in your garden and dispose of them far away.
- Prune infected parts as soon as you notice they are infected with powdery mildew.
- Water the roses regularly to remove the moisture lost to the fungal spores.
- Mulch your garden heavily to reduce water loss.
- Fertilize your garden to provide supplemental nutrients for your roses.
- Prune the roses to improve air circulation.
- Water the roses mid-morning so that the leaves can dry quickly.
- Use fungicides when conditions support the growth of powdery mildew.
- Consider removing some plants to create room for ventilation, especially if the rose plants are too close together.
Rose dieback affects the stem of roses. As the name suggests, the branches die backward towards the base of the stem or crown.
Stems affected by dieback cannot support new growth. As the branch dies, the risk of the entire plant dying is high.
If you don’t take measures to control rose dieback, it will affect all the branches in your rose plant. No shoots, leaves, or rose blooms will grow on branches with dieback. If it goes all the way to the crown, the rose plant will not come back at all.
Rose dieback is caused by multiple issues that can be difficult to detect. This makes treatment difficult.
Here are some of the causes of rose dieback.
- Insect infestations
- Plant age
- Insufficient nutrient levels
- Poor care and maintenance
Unfortunately, some fungal diseases take advantage of roses with dieback.
Some opportunistic diseases that further complicate the treatment of dieback include the following:
Rose Canker (Coniothyrium spp)
One of the most common opportunistic diseases accompanying rose dieback is rose canker. The black splotches attack shoots and canes of roses affected by dieback.
The disease is usually a result of using an unclean pruner on multiple rose plants.
Signs of gray mold include dark brown spots on petals, leaves, and stems. The spot forms close to infected parts of the rose plant.
When moisture levels are high, the spots take over the entire leaf and progress to the entire plant. If left untreated, gray mold kills rose gardens.
Control and Management
Rose dieback is quite destructive and is one of the main reasons rose gardens die and never come back.
However, you can do the following to prevent and even control its spread:
- Prepare the soil in your garden well to facilitate easy root penetration.
- Avoid planting roses in soil previously used for roses.
- Use soils with great drainage.
- Use rose fertilizer.
- Use mulch at least 2 inches (5 cm) thick for frost protection.
- Prune stems and ensure you get rid of all the dead stems. Ensure you do it before the dieback gets to the crown.
- Use fungicides that target foliar diseases.
Other diseases that kill rose gardens include downy mildew, Cescospora leaf spot, Rose Rosette Disease (RDD), and Crown Gall.
2. Pest Infestations
Pests can also be a menace to rose gardens. The pests destroy the leaves and flowers. They also distort the foliage.
The pest infestation destroys the rose plant’s ability to support new growth in the long run. If left unchecked, pests will kill your roses.
The chart below outlines the pests that roses are prone to, in addition to some methods for controlling them:
|Aphids (suck sap)|
|Rose slugs/sawflies (skeletonize leaves)|
|Rose Cane Borers (cause dieback)|
3. Lack of Nutrients
Roses are heavy feeders. This is why, unlike other flowers, you will come across fertilizers made specifically for roses.
The rose plant relies heavily on its foliage to make flowers. So, it needs to feed heavily to keep producing foliage to support the flowers.
The nutrients also contribute to the roses’ ability to withstand pest and disease infestations.
Fertilize to Provide Essential Nutrients
If your rose garden has many roses or other flowers, you need to use enough fertilizer. Other plants, including weeds, feed on the nutrients meant for the roses. If the garden is adjacent to your lawn, the grass may also be drawing nutrients from the rose garden.
If you are to make up for the lost nutrients, you’ll need to feed your roses regularly. Otherwise, they will start showing signs of nutrient deprivation. The rose plants may stop producing new foliage, the leaves might develop yellow margins, and the plants could have stunted growth and smaller blooms.
If you don’t start fertilizing the roses (every 2-3 weeks), your plants will start dying. When the roots become weak, you may not get your roses back.
4. Over Fertilizing
While fertilization is a great way to supply your roses with adequate nutrients, roses can also die from over-fertilization. The leaves wilt and turn brown when you use too much fertilizer.
During the growing season, add granular fertilizer (slow release) every 3 weeks instead of liquid fertilizer if you are worried about over-fertilizing. Use less fertilizer during the winter months.
You can also use signs of nutrient deficiencies to guide you on when to use fertilizer.
The following are common signs of nutrient deficiency in roses:
- Rose leaves turn yellow with green veins when the rose plants have an iron deficiency because iron deficiency interferes with chlorophyll production.
- A manganese deficiency is characterized by a change in the green color of leaves. Instead of the usual dark green, the leaves take a lighter shade of green.
Roses, like other plants, can die when they lack water. They may not like it when you get their leaves wet, but the roots of roses need a lot of water to feed the plant and support foliage growth, especially when the plant is actively growing.
Your roses will start drying if you don’t meet the watering demands.
6. Wrong Growing Conditions
A rose garden’s location is crucial to its survival. Roses need 6-8 hours of sun each day. However, they also need protection against harsh weather patterns, such as strong winds and extreme heat.
If possible, position the garden close to a building or trees. The ideal location for your rose garden provides full sun but also protection in case it gets windy. The building and trees also provide shade against extreme heat at specific times.
7. Poor Pruning Techniques
Roses need to be pruned regularly, but you need to do it right. When pruning infected branches, you need to dip the pruning tool in water to avoid infecting healthy canes. You also need to ensure the tool is sharp for a nice, clean-cut.
When improperly pruned, roses will have weak canes and poor air circulation. The roses will eventually become unproductive.
8. Failure to Mulch for Winter
Many rose plants tend to die during winter, especially if the variety cannot withstand the frost. Proper winter care and protection ensure your roses bounce back in the spring.
Apply 2 inches (5 cm) of mulch at least 2 inches (5 cm) away from the base of the stem to help retain moisture. It also protects the roots from frost damage. Ensure you don’t cover the crown because the plant will die if it rots.