Watering Roses

Roses need water to grow to their fullest and to produce large, long-lasting flowers with rich color and excellent substance (thick, sturdy petals). In areas with steady and sufficient rainfall, supplemental watering should not be needed. Even in these regions, however, extraordinary conditions may exist. Sometimes it does not rain deeply or frequently enough for roses to survive and prosper. Sometimes extreme heat or wind evaporates soil moisture and causes leaves to transpire excessively. When rainfall or other natural water sources are insufficient, watering is necessary.

Quantity and timing

Roses need to be watered throughout the period when they are growing or flowering. Roses need 1 inch of water per week, from rainfall or other sources. Watering more or less depends on the circumstances. The condition of the soil, the temperature, and the proximity of other plants all affect the watering requirements of your roses.
Sandy soil dries out more quickly than clay or loam and thus needs more frequent watering, perhaps every five days instead of once a week. Gardens in hot, dry, or windy surroundings also need more frequent watering than normal. In areas where the soil is heavy and retains moisture, less frequent watering is necessary. Overwatering heavy soil can keep rose roots overly moist, making them prone to root rot.

Reaching roots

It is important to water deeply (12 to 18 inches) but as infrequently as possible to encourage deep roots. In temperate climates a weekly watering is usually sufficient. Roses with deep roots will be stronger, healthier, and more drought-resistant than those with shallow roots. Water early in the day so that the leaves do not stay wet through the night, as this fosters disease, especially if you are using an overhead watering system rather than a drip system. If the soil is heavy, apply water slowly and evenly so that it is absorbed rather than lost through surface run-off.

Testing to ensure proper watering

To ensure that you are watering often enough, take a soil probe one week after you have watered. If the soil at the bottom of the probe has completely dried out, you need to water more than once a week. Try watering every five days to see if the soil passes the test. If it does not pass, shorten time between watering until it does. If, however, the soil is still moist at the bottom of the probe when you first test it, an interval of 10 days might be better.
Adding organic matter such as compost or leaf mold to a sandy soil can help it hold moisture so that watering is not needed as frequently. A mulch applied to the top of the soil not only holds moisture but also deters weeds, which are notorious water thieves. If your roses are planted near a large tree or shrub, you may need to compensate by giving the roses extra water. Probe the soil around the roses as described above to determine whether more water is needed.
One exception to the watering rule is newly planted roses. They should be watered daily for about a week and then every few days until new growth is evident. At that time they can be watered in the same way as any other rose in the garden. If they show signs of wilting, you need to keep up the more frequent watering until they become established.

Roses in containers

Roses growing in containers require more frequent watering than the same plants growing in the ground. Water is quickly depleted from the limited growing space in a container and can evaporate from the sides of porous pots. In hot, windy locations, container plants may need watering once a day or more, with smaller pots needing more frequent replenishing.
Check the medium in the container every day, and water when the top becomes dry, applying water until it runs out of the drainage holes. Use a type of nozzle known as a bubbler or soaker head, which administers water in a soft flow, to keep holes from being created in the planting medium. A water wand, which is a long tube with a nozzle at the end, is useful for watering hanging baskets or out-of-reach containers. Roses can be watered with a watering can, but if you have many plants, this method consumes time.
To help roses survive the winter, make sure that the plants are watered before the soil freezes. If it has not rained in fall, apply a deep watering before draining the hoses and shutting down the watering system during cold weather.

Watering methods

There are a number of ways to supply water to rosebushes. The most traditional is with hoses and sprinklers. The equipment for overhead watering with sprinklers is less expensive than that for drip irrigation. However, overhead watering uses much more water and can promote fungal disease. Because of increasing concern about water conservation, many people are turning to drip irrigation, which is the most efficient way to water.

Drip irrigation

Drip irrigation uses less water than overhead watering because the water is applied only to the ground where it can be absorbed by the roots. Irrigation prevents foliage and flowers from getting wet, thus protecting them from diseases and water damage.

Emitter system

There are two major kinds of drip systems: emitters and soaker hoses. An emitter system consists of a rigid main tubing interspersed with small holes from which flexible, narrow tubes called emitters extend. The ends of the emitters are capped with small nozzles that emit water in a gentle drip or stream. These are placed wherever there is a plant to be watered; if there are no plants for a stretch of the main tubing, the holes can be plugged.
An emitter system can be laid on the ground, buried, or hidden beneath a layer of mulch. It is better to bury the system, as this keeps the ultraviolet rays of the sun from weakening the plastic hoses and insulates the system from winter freezing. It is also more attractive. In areas with cold winters, an aboveground system should be removed in autumn to prevent it from freezing and cracking. The holes in an emitter nozzle system are very small and can clog easily. To prevent clogging, install a filter at the water source and clean the filter once a month.

Soaker hoses

Like emitter systems, soaker hoses deliver water directly to the soil at the base of the plant. But unlike them, they exude water through pores or pinholes all along their length instead of at designated locations. The oldest kinds of soaker hoses are made of heavy canvas through which water seeps into the ground. Another type is made of flat plastic, punctured with pinprick-size holes every few inches. The newest types are the tubular micropore hoses, which have a sponge like network of tiny holes through which beads of water "sweat" over the surface of the hose. These hoses are made from white plastic or recycled black rubber tires.

Sensors and timers

Any type of irrigation system can be set up to work automatically, using a moisture sensor or a watering timer to turn the water on and off.
Roses can be watered with sprinklers or other overhead methods if watering is done in the morning so that the foliage has time to dry out.
Leaves and canes that stay wet overnight are vulnerable to disease. For this and other reasons, it is far better to water with a drip irrigation system or with soaker hoses. But even if you have a drip irrigation system, occasional overhead watering every several weeks can help rid leaves of dust and spray residue, and can discourage spider mites, which thrive on foliage that is hot and dry. The oscillating type is usually better than the rotating kind for large gardens, because its rectangular coverage results in less overlapping and thus less wasted water.

Hoses

Hoses, like sprinklers, come in various sizes. You should buy a hose that is long enough to reach across your garden and that is 5/8 inch in diameter (rather than the less common 1/2 inch) so that it can deliver more water. There are also 3/4-inch-diameter hoses, but these work well only with very large sprinklers and with very high water pressure. Hoses are made of plastic or rubber; those of rubber are less likely to kink, while those of plastic are more flexible. Plastic hoses do not work well in cold areas because they lose their flexibility and are likely to crack. Some hoses are reinforced with an internal mesh that protects them against bursting and kinking.
You can reduce kinking by coiling hoses when not in use. A wall-mounted hose hanger or a mobile hose reel makes this job easier. To keep hoses from dragging over low-growing plants, place guide stakes at the corners of the beds or in other strategic positions. Several types of nozzles are also available. Handheld pistol nozzles can deliver water from a hard spray to a fine mist, as can nozzles with twist controls. The hard spray is for knocking aphids and other pests off plants, the intermediate spray is good for general watering, and the fine mist can be used to raise humidity. Fan-shaped nozzles give a wide, coarse spray that is useful for watering small rose beds. Soaker heads are good for watering containers or filling the catch basins of plants.
Adding water to the root area of a newly planted rose does not require a nozzle. Simply place the end of the hose into the catch basin around the plant and let the water run gently until the catch basin is full.