Marin Rose Society - Rx for Healthy Roses

Rx FOR HEALTHY ROSES - CULTURAL CARE
by Nanette Londeree, Master Rosarian

“An ounce of prevention is worth a pound of cure,” proffered the wise Benjamin Franklin more than 250 years ago. While it’s not likely he was referring to the care of roses, it’s completely applicable and sage advice to the twenty-first century gardener. Our first Rx (prescription) for healthy roses focuses on good cultural practices. By providing optimal growing conditions, plants are better equipped to ward off some diseases and tolerate damage by pests. By preventing (or at least reducing) pest and disease problems, you’ll have more abundant bloom, and save the time, money and effort you might have spent on controlling or eliminating them.

Cultural methods include:

selecting plants with known disease resistance

planting in an area with plenty of sun and air circulation

developing healthy, well-draining, friable soil

providing adequate water at the appropriate time and method

supplying a balanced level of needed nutrients

pruning plants to maintain vigor and promote good air circulation

mulching to conserve water and reduce weeds

removing debris and infested plant material

providing habitat for natural enemies

Hannah Gordon While many of the most important cultural methods are things a gardener can control, weather isn’t one of them. You can’t limit the amount of rainfall, but you can ensure good drainage. Conversely, the months of drought in our area are totally nature’s call, but when and how you irrigate is yours. The soil your house sits on comes with the property, but if it’s not to your liking, you can amend it to create the quality you desire.

Selecting plants with known disease resistance

You can get a head start by choosing rose varieties that perform well in our area. Check out plants in public gardens, friends and neighbors yards and at nurseries, especially at the end of the season. Plants that appear vigorous, with little sign of pests and disease are likely good candidates for your garden. Purchase plants from reputable sources and choose ones that are disease free and appear well cared for. Some super healthy examples in my garden include the white picotee floribunda ‘Hannah Gordon’ (ARS 8.8), the sumptuous blush white miniature ‘Gourmet Popcorn’ (ARS 8.7), the pearly-pink climber ‘Clair Matin’ (ARS 8.9) and the potently perfumed new grandiflora, ‘Rock & Roll’ (no ARS rating).

Gourmet Popcorn Planting in an area with plenty of sun and air circulation

Location, location, location! To grow great roses, plant in a place that gets plenty of sun, is protected from wind, and has adequate space to spread out. Go for full sun – roses are sun-lovers and need a minimum of 5 – 6 hours each day to produce abundant flowers. Don’t plant a rose under or too close to a tree since most trees, with their big, greedy roots systems, compete with roses for water and nutrients. Allow plenty of space around the plant (considering its size at maturity) so you have good air circulation.

Developing healthy, well-draining, friable soil

A golden rule of gardening says, "If you treat your soil well, it will treat your plants well." Supplying your plants with the necessary ingredients starts with the soil. Perfect soil has good tilth – the equivalent of good health in humans. It consists of about 50% solid material, 25% air and 25% water. The solid portion would be mostly loam (20 – 30% clay, 30 – 50% silt and 30 – 50% sand) with a hefty portion of organic material. The crumbly, dark soil would be teaming with microorganisms and earthworms have plenty of nutrients and a pH between 6.5 and 7.5. Good drainage is an important place to start, then regularly amend soil to keep it healthy and friable.

Rock & Roll Providing adequate water at the appropriate time and method

Stress in plants can leave it more vulnerable to attack by pest and diseases. Lack of adequate water is one of the most common stressors and can be easily managed. Adjust your watering schedule to the weather and irrigate deeply but less frequently. Water in the early morning hours when temperatures and wind speed are the lowest, and don’t wet the leaves unless there’s plenty of time and warmth for them to dry (most fungal leaf diseases require four+ hours of continual leaf wetness to infect.) Install irrigation devices that are the most water efficient for each use and check sprinkler systems and timing devices regularly to ensure proper operation.

Supplying a balanced level of needed nutrients

Roses will do their best with a balanced diet; there is no prescribed “right” diet. Experiment with the bounty of available materials and find something that works for you and your plants. Just do it in moderation and water well before and after feeding. Avoid promoting lush, succulent growth - it actually is an attractant to many insect pests.

Pruning plants to maintain vigor and promote good air circulation

While it’s not the favorite task for the gardener, pruning plants is important for the health of the plant. Removing the 3-D’s – dead, diseased and damaged canes and stems, helps to invigorate the plant, increase air circulation which in turn reduces the opportunity for common fungal diseases, It also keeps the plant the size and shape you desire.

Mulching to conserve water and reduce weeds

Mulching is one of the easiest and least expensive things you can do in the garden that provides a plethora of benefits. By simply adding a layer of mulch to the soil in the spring, you can moderate soil temperature, reduce water consumption, add nutrients to the soil, reduce erosion, encourage earthworm activity, reduce weeds, improve the garden’s appearance, save time and save money. Dollar for dollar, that’s a pretty good return on your investment!

Removing debris and infested plant material

Cleaning up the garden, especially after pruning, can help reduce disease by eliminating the habitat in which the infectious agents and insect pests overwinter. Remove diseased plant debris (fallen fruit, twigs, and leaves) and toss them in the green waste can, not your compost pile.

Providing habitat for natural enemies

Like any living creature, the good guys need food, water and shelter, all generally available in the garden. Diversity in plants encourages a range of beneficials; sequentially flowering plant species provide natural enemies with nectar, pollen, and shelter throughout the growing season. Tolerating low populations of plant-feeding insects and mites ensures that food is available to the hungry garden helpers. Also, reduce dust – it can interfere with the good guys and result in outbreaks of pests such as spider mites.

So consider following old Ben Franklin’s advice about prevention and start off this rose growing year with great cultural practices. You may save yourself tons of work!

By Nanette Londeree (photos and text)

Rx FOR HEALTHY ROSES - CULTURAL CARE by Nanette Londeree, Master Rosarian

Rx FOR HEALTHY ROSES - CULTURAL CARE
by Nanette Londeree, Master Rosarian