Training roses is essential if you want the rose to cover a surface uniformly. When a rose climbs a tree trunk, rambling varieties use their thorns for support, but against a wall, thorns are of no use. The solution is to train the stems, starting horizontally with the most vigorous in order to force them into flower. Fix trellis or steel wire vertically every 2 ft. (60 cm). Guide the stems along the support as they grow and attach them loosely to it. Repeat this operation for fifteen days if so in varieties that develop quickly. For less exuberant plants, you only need to guide the stems at pruning time and to attach the new shoots in place of the old.
TIMELY INTERVENTIONS
There is no need to fuss about your rose at every opportunity. You will only give it bad habits! Only get involved when there is a real problem to sort out, like a fungal infection or other threatening disease.
REMEDIES AGAINST THE MOST COMMON DISEASES AND PESTS
Powdery mildew
Following a spell of dry weather, this may affect climbers and ramblers that are trained against the wall, at the beginning of the summer, often before flowering occurs.
Symptoms: a white powder at the extremities of the young shoots and on young leaves. Unless treated, it will spread to older leaves and the floral buds, preventing them from opening. Powdery mildew also diminishes the rose’ resistance to other diseases, particularly black spot.
Treatments: as a preventative measures, spray sulphur in late spring, before flowering, and repeat as necessary. During dry spells. Roses susceptible to powdery milder should be water regularly, well fed with food that does not contain too much nitrogen (which can “feed” the disease), and mulch before summer.
Black spot
This disease is particularly virulent in newer variants of rose and during wet weather.
Symptoms: little black spots appear on the leaves, spreading rapidly, occasionally going so far as to attack can result in the plant losing all its leaves.
Treatments: at the first sign of black spot spray the plant with fungicide containing Mancozeb. Gather all the fallen leaves and burn them to prevent further contamination. In varieties particularly prone too attack, treat both stems and leaves preventively as soon as they begin to show and spray again every fifteen days. To avoid disease, choose a good location that is not too shaded and soil that is well drained; avoid feeds that have excessive nitrogen and mulch abundantly in the summer month. Be especially careful when watering not to wet the leaves.
Rust
Although not especially common, rust, which is often fatal, attacks very sensitive varieties first, before moving on to less sensitive roses nearby. Warm, humid weather and oil deficient in potassium favors its development.
Symptoms: Orange pustules that are sometimes hard to see form first in the underside of the leaves before spreading rapidly to the whole plant, particularly on the stems and around the thorns. The pustules blacken, signifying that the leaves are dead.
Treatments: spray the underside of the leaves with an antirust fungicide, repeating the operation several times if necessary. Gather and burn all dead leaves to prevent the disease reappering. If despite these measures the disease persists and goes on to attack several plants, do not hesitate to uproot the diseased plants and burn them. Do not replant roses in the same location without changing the earth.
HOW TO DEFEND AGAINST PESTS
Aphids
Symptoms: aphids secrete a form of honeydew that sticks to the rose and which rapidly plays host to a sort of ugly black soot. It becomes more noticeable when the aphids invade in large colonies.
Treatments: do not wait for the colonies to develop. As soon as you spot the first aphids, spray the contaminated area with a jet of water. In more serious cases, use a pesticide that is recommended for killing aphids. If the problem persists, repeat the operation using an aphicide with a different active ingredient. Unfortunately, aphids have begun to grow resistant to the products traditionally used to destroy them.
Sawfly
Symptoms: this pest damages the rose’s leaves in which it rolls up its larvae and the resulting cocoon is difficult to destroy.
Treatment: at the first sign of attack, spray with pesticide. If attacks continue, apply preventative treatment the following year in the spring.
Rose chafer
The rose chafer is a large, metallic green beetle about ¾ in. (2cm) long.
Symptoms: rose chafer eats flower buds, petals, anthers, and even the leaves of plants.
Treatment: act quickly once you spot rose chafers by spraying with pesticide.
Thrips
Thrips are tiny four-winged flies that swarm during hot, stormy weather.
Symptoms: thrips eat the flowers and the foliage of modern roses, deforming them in the process. As a sign of an attack is the blackening that occurs on the edges of petals.
Treatment: use an appropriate pesticide and renew the treatment if necessary.
REGULAR DOSES OF FERTILIZER
The secret of well-fed roses is to spread feeding regularly throughout the year. The first should be given after the plant’s end of winter prune: work a handful of rose feed into the earth around the base of the plant. If weather conditions are not suitable at winter’s end, then hold off until mid-spring when the weather is more clement. This annual dosage is sufficient for plants that flower only once. But repeat flowerers tend to be hungrier and to encourage flowering, give a second dose in early to mid summer, just after the first flowering.
ROUTINE TASKS ESSENTIAL FOR SUCCESS
Deadheading, a judicious compromise In order for your rosebushes and rose beds to continue looking good, deadhead faded or wilted flowers wherever possible. DO not cut where the flower grows from the stem, instead cut the lower down, just above the first large bud. Bear in mind that if you do this you will not be able to enjoy the rose hips that are produced in late summer and fall and which is in certain varieties can be stunningly beautiful. This particularly true in non-remontants, and it is why these should be deadheaded. On the other hand, deadheading repeat-flowerers in mid summer ensures an abundance of flowers at the end of the season.
Watering and weeding, summer jobs
The two chores that signal the arrival of summer are watering and weeding. Both newly planted and older roses should be watered regularly during the summer. Pot roses tend to require most water, and in summer these should be watered daily, or even twice a day if the weather is particularly hot. Newly planted climbers that are being trained to cover a wall also require copious quantities of water. Weeding should be carried out frequently starting in spring, and especially before mulching. Be careful not to let weeds take hold at the foot of your rosebushes, and be particularly careful with newly planted roses which risk being suffocated by weeds that compete for water and nutrients. Mulching before the arrival of hot weather reduces the need for these two tasks. A 2 in. (5cm) layer of straw, grass clippings, flax shives, or decorative bark will do the trick. Not only does this mulch prevent weeds from growing, it reduces the need for watering during the summer by keeping the roots moist.
Removing root suckers that soak up sap Root suckers, which can be very vigorous, grow underground starting at the graft point. They should be removed because they absorb the sap from the rose itself. Expose the graft point by scraping the earth away and cut the suckers off at the point of contact.
ADAPTING TO CLIMATIC CONDITIONS
Solutions for hot climates:
- In hot climates, mulch well in advance of the hot weather that arrives in late spring and leave the mulch in place until early fall. Under no circumstances attempt to plant in late spring, failure is almost guaranteed; better to wait until the first rains of the fall.
- Roses should be protected from beating sunlight and direct exposure to the midday sun; choose an exposure that offers some shade.
- Reserve your watering for newly planted roses and try to accustom older roses to getting by without watering. Water the soil around the base of the plant, avoid getting water on the leaves.
MULCHING AND MOUNDING, ESSENTIAL IN COLD WATERApart from the mulching already mentioned as necessary when planting, in particularly cold weather it is also necessary to protect the exposed parts of more sensitive roses, namely climbers, standard roses, and weepers.
- To strengthen resistance, avoid adding fertilizer after midsummer; in this way, the young shoots will have time to turn into wood before the arrival of the cold season.
- The best protection against the cold is to mound the rose by covering the base in a little pile of earth, 12-16 in. (30-40cm) high, that will protect it from the cold. The parts buried underground are rarely at risk of freezing. Roses whose grafting point is higher up such as standard roses or weepers can be bent toward the ground and then covered in soil.
- Large plants – shrubs and climbers – should be given extra protection if the weather is especially harsh; swaddle them with conifer branches, straws, of frost fabric. Often, the greatest risk comes from the changes in temperatures between night and day as the days begin to improve in late winter and early spring. If you use plastic as wrapping, ensure it is perforated.
- Mound and mulch bush roses by surrounding them with a mesh against which the dead leaves or straw can lie. In general, most old roses and German-bred varieties are very resistant to frost and do not require this sort of care. After about of cold, carefully inspect the wood and do not hesitate to remove any damaged stems, cutting back as far as ground level if necessary. The plant will only grow all the better for it, provided you have afforded them sufficient protection when they needed it.
AVOID TRELLISSING TOO CLOSE TO THE WALL
Placing a trellis too close to the wall encourages the development if diseases such as black spot and powdery mildew. Make sure there is sufficient room for air to circulate between the rose and the vertical surface.
SPECIAL FEED FOR ROSES IN POTS
While roses planted in soil, particularly shrubs and non remontant varieties, do not derive ant great benefit from rose feed, this is not the case for roses in pots. Choose a slow-release, high performance feed specially developed for these types of plants and use by professional. Although expensive, only a small amount (roughly a handful) is required and a single dosage per season is sufficient.
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