Roses remain as one of the most popular additions to a garden, repaying many-fold the efforts put into their care with their beauty and fragrance. For roses, “a healthy vigorous well-grown plant will experience the least pest and disease problems,” remains true. It is to this end that every possible sustainable technique be used to create a system that produces strong beautiful roses season after season. In general, roses are high input plants—requiring more fertilizer, water, maintenance hours, and possibly pest monitoring than many other plants. High input areas should be reduced in size yet placed in highly visible locales to fully enjoy the benefits they provide.
To have beautiful and healthy roses:
- Choose roses that have shown resistance to diseases experienced in our coastal area and acquire plants from a reputable source. Visiting a rose garden, such as the Santa Barbara Rose Garden, to observe prospective choices can be very helpful.
- Plant in a sunny location with good air circulation. Roses are somewhat tolerant of less than perfect locations, but performance will probably suffer.
- Prepare the soil with generous amounts of composted organic matter and provide good drainage. Inoculate the soil when planting with effective micro-organisms. Beneficial bacteria/fungi blends can be purchased that help plants become established. These microorganisms form symbiotic relationships with the roots of plants aiding them in absorbing nutrients and water and suppressing disease. An organic fertilizer mixed in the backfill will provide for the nutritional needs of the new roses. It is very important when planting to have the root crown right at the soil surface.
- Correct irrigation begins at planting time and is important throughout the year. The root system of roses is very near the soil surface so it can easily dry out. The stress of re-growing new roots lost to desiccation will predispose the rose to disease and even insect problems. Do not cultivate the soil in the root area of the roses and maintain a layer of finely shredded organic mulch over the whole planting bed. Choose an irrigation system that waters the entire rose bed. Minisprayers combined with drip works well. Do not be afraid to wash the rose foliage weekly. Remember the fog is going to get them wet anyway so washing removes many of the fungal spores that have settled. Spray them off in the morning so they have a chance to dry before the cool of evening.
- Use slow-release organic fertilizers. The activity of the soil organisms transforms the organic fertilizers and the organic matter (mulch) into nutrients the roses can use when they need them.
- If you live near the coast and have poor air circulation in your rose garden, foliar diseases will probably be a concern. Spray weekly with compost tea to manage foliar diseases. The compost tea provides a film of living beneficial organisms on the leaves of the roses that helps prevent fungal disease spores from infecting the plant. Remove infected leaves to help prevent re-infection of healthy foliage. Maintain the overall health and vigor of the system to prevent non-foliar disease problems, such as stem canker. Proper pruning methods and sterilization of pruning tools are also important.
Insect Ecology: Wise management of the insect ecology is essential in sustainable management. Chemical sprays of any kind applied to the leaves will harm beneficial insects and destroy soil biology leaving the roses weaker and more susceptible to attack.