Seasonal Rose Maintenance

It is important to deadhead rose blooms as they fade. This keeps the plant cool and nourishes new growth. Clean up all spent flowers and debris, as these harbor diseases.

Monitor the plants for aphids and mildew, as these flourish in hot weather. Washing leaves daily, especially the undersides can help control aphid infestation.

Spring Pruning

This is a good time to prune most roses, particularly repeat-blooming cultivars. The plant is beginning to wake up and put out fresh growth but is not fully covered in leaves yet, making it easier to evaluate winter damage. Pruning before the rose blooms also makes it easier to shape and reduce size if needed.

The main goals of spring pruning are to remove dead or diseased canes; increase air circulation and prevent tangled branches; thin the plant to avoid overcrowding; and encourage the growth of flower-producing wood. You can also use this opportunity to apply dormant oil, a spray that coats canes, buds, and leaves and suffocates the spores of overwintering pests and fungal diseases.

It is important to cut back to a point just above the graft union, which is a swelling or knot a few inches above where the roots start. This helps prevent fungus infection from entering the plant through the graft and stealing nutrients.

You should also prune out one-third of the oldest canes on your roses, leaving about 3 to 5 healthy stout canes evenly spaced around the plant and all with outward-facing buds. This keeps the rose from becoming an overgrown thicket of poor-flowering canes, and it also encourages vigorous new growth that will carry next year’s flowers. Also, be sure to remove crossing or rubbing canes. These can whip against each other during rainy weather and cause wounds from thorns, increasing the likelihood of botrytis dieback.

Summer Pruning

Most gardeners quickly become adept at watering and fertilizing their roses but it takes a little more time and effort to learn the fine art of pruning. Some gardeners are hesitant to learn this skill because they fear that they may harm their roses, however it is important to carefully prune your plants in order for them to be healthy and produce an abundance of flowers.

As summer progresses, it is a good idea to dead head any spent flower heads. This helps to keep the plant aesthetically pleasing and also encourages reblooming. To do this simply cut the old flower head off just above where it meets the stem in established shrubs and at ground level in newer roses. When cutting, aim to make the cuts similar in length to those you would cut when making a bouquet.

If you have a very overgrown rose bush, it is also a good idea to remove any winter kill or damaged canes and thin out the centre of the plant by about one-third. It is also a great time to apply a light fungicide treatment.

Remember that you should always prune in dry weather, never after a heavy rain or while the leaves are still wet. If you do not do this, the cambium tissue beneath the bark can be scorched and that leads to sunburn and a very weak stem. It can even lead to the formation of stem canker and fungus disease.

Fall Pruning

If you live in a climate with cold winters, covering rose plants with soil or mulch is a good idea. This protects the plant from heavy rain and snow, which can compress or bury the roots, causing damage and stress.

If your roses are growing in a garden zone that is colder than their hardiness rating, you will need to cover the plants for at least some of the year. It is best to cover the plants as soon as they begin to go dormant in fall, preferably before frost.

A light pruning is also important for the health of your roses in the fall. It removes any diseased or broken stems and branches, improving the plant’s overall appearance and allowing energy to be directed to new growth in spring rather than fighting off pests and diseases that are drawn to damaged areas of the plant.

Always use clean shears when pruning to avoid spreading diseases from one plant to another. Before using your shears, sanitize them with a 70 percent solution of rubbing alcohol, then clean them again between each cut. All pruning cuts should be made at an angle, as this helps water run off more quickly and avoids rot on the stem. This will help prevent the fungus that causes black spot, powdery mildew and other problems in the garden.

Mulching

Mulching helps protect roses by retaining moisture, controlling weeds and providing a source of nutrients as it decomposes. It also provides some protection from wind, ice and snow. In addition, mulching will help keep soil temperatures more even, which can be especially important for shrub and climbing varieties in climates with extreme temperature variations.

It is best to lay a 2 to 3 inch layer of organic mulch (such as wood chips or shredded bark) over the soil in your rose garden. Any deeper and the mulch can suffocate the roots, making it hard for water to penetrate the surface. The organic material also can deplete the nitrogen in the soil, so it is important to add an additional dose of a slow-release rose fertilizer when using this type of mulch.

Applying a thin layer of organic material in the spring will also help to suppress weeds. The weeds that do germinate will be buried under the mulch, and it is usually possible to pull them out without disturbing the rose bush.

Some of us have found that mulching may also reduce fungal diseases, such as Blackspot, by reducing the splashing of spores from hard ground surfaces onto the leaves. Be sure to use a organic material that will not deplete the nitrogen in the soil, such as compost or aged manure.