University of Illinois Extension

 


Sharon Yiesla, Unit Educator, Horticulture, Lake County

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Springtime Is Rose Time

As the weather warms, it will be time to think about roses. When planting a new rose, site selection is important. There are several things to consider. Roses need a minimum of 6 hours of sun per day to grow well and to produce their flowers. Consider planting roses in a south facing exposure for maximum sunlight. An east facing exposure is also good as it will receive morning sun. Morning sun will hasten the drying of dew from the plants and be cooler and less stressing than afternoon sun.

Good air circulation is also important. So many of the disease problems common to roses are more likely to occur when the plants stay wet for extended periods of time. A site with good air circulation will keep plant surfaces drier and reduce the incidence of disease. Avoid planting roses too close to one another, to other plants or to buildings or other structures.

Roses must have soil that drains well or they will do poorly. You may need to amend the soil with organic matter or even consider raised beds, if the drainage in your yard is not sufficient. Roses will grow best if the soil is on the slightly acid side (pH 5.5-6.5).

Spring is the time to plant roses in northern Illinois. Planting in spring gives the plant the entire growing season to become established before facing the rigors of winter. Bare-root roses should be planted while they are still dormant. Container grown roses may be planted throughout the growing season, but early is best. Our northern winters can be hard even on established roses; newly planted roses should be given every possible chance to succeed. Avoid fall planting in northern Illinois.

When planting roses, soil preparation and size of planting hole are both important. Whenever possible, enrich the soil with organic matter. This will improve drainage and make the soil more fertile. It will be most beneficial if you can prepare a planting bed (rototilling in organic matter as you would for a perennial or vegetable garden) rather than just amending the planting hole itself. This encourages the root system of the plant to spread out into the prepared soil, and develop more fully.

After the planting area has been amended with organic matter, you are ready to dig holes for the individual plants. Be sure to dig a hole that is both deep enough and wide enough to accommodate the root system. Don't dig a small hole and try to "squeeze" the roots in.

If you are planting a bare-root rose, you will have to build a soil mound to support the plant (bare-root plants come with no soil of their own). The mound supports the plant and allows you to spread the roots out in a natural pattern. Special care must be taken with bare-root roses. The roots should be soaked in water overnight, prior to planting, to insure that the roots are fully hydrated. The canes and roots may also need to be pruned. Try to maintain 3-5 canes per plant and prune them to 3-5 buds per cane. Prune the roots so that they are a little longer than the length of the canes.

As you place the plant in the planting hole, be aware of how deep you set the plant. In northern Illinois’ harsh climate, roses that are grafted should have their graft union 1-2 inches below the soil line to prevent winter kill of that graft union. Roses that are growing on their own roots can be planted at the same level at which they were planted in the nursery. The soil line is often apparent on the crown of the plant.

Once the rose is planted, be sure to water it in thoroughly. Transplants often have limited root systems and need regular watering to insure that they become established in a timely fashion.

As with any plant, the care given by the gardener greatly determines the health and vigor of the plant. The following basics on watering, mulching, fertilizing and winter protection will help keep roses in good health.

Proper watering is essential to the health of any rose. Roses need soil that drains well, but they also demand an ample supply of water (about 1 inch per week; more in the heat of summer). When you water, do so deeply and infrequently. This will encourage the development of a strong, deep root system. Avoid frequent, shallow watering which will cause roots to be very close to the soil surface. Since roses are prone to some serious fungal diseases, it is wise to direct water to the soil and avoid wetting the foliage. Leaves that remain wet for long periods of time are more likely to become diseased.

Soaker hoses work very well in the rose garden, delivering water directly to the root system and keeping foliage dry. Soaker hoses are efficient watering devices since the water goes directly into the soil and the loss to evaporation is minimized. The hoses can be placed under the mulch so they do not detract from the beauty of the garden.

Mulching in summer is very beneficial to roses. Mulch helps conserve moisture, reduce competition from weeds and keep soil temperatures cooler. Mulch should be applied in late spring after the soil has warmed a bit, but before the heat of summer sets in. Apply about 2-3 inches of mulch over the root systems, but do not pile it against the canes as this could promote rot.

Well-aged organic mulches do well around roses, as they will release nutrients when they break down. Fresh bark and wood chips, however, will rob the soil of some nitrogen as they decay. You may need to add a small amount of nitrogen to compensate for this.

Fertilizing is very important to roses; they are heavy feeders. If an organic mulch is used, it will supply some nutrients, but additional fertilizer will still be needed.

When shopping for fertilizer, note the three numbers on the label. These numbers indicate the amount of nitrogen, phosphorus and potassium in the fertilizer. Phosphorus is the nutrient which helps promote good flower production, so purchase a fertilizer with a higher proportion of phosphorus, the middle number (such as 5-10-5). It is possible to purchase specially formulated fertilizers that are sold as 'rose food'. You can also buy an all purpose fertilizer (like 10-10-10).

The first application of fertilizer can be made in spring after the danger of frost is past. Further applications can be made about every six weeks. Fertilizing should be stopped after July to allow the plants to harden off for winter. Be sure to follow the label directions.

Since northern Illinois can experience fairly severe winters, protection must be considered. The type of winter protection will vary, depending on the types of roses you are growing. Some roses, such as species roses, some of the shrub roses, and some of the old garden roses are quite hardy and require little or no protection.

Many of the modern hybrids commonly grown today require some winter protection. One of the simplest methods of winter protection is mounding loose soil, compost or shredded leaves around the base of the plant. These materials should be mounded to a depth of 6-12 inches. It is important to use materials that will not compact easily. If the mound becomes compacted it may hold too much moisture around the base of the plant, especially if the rose is planted in a heavy soil that drains slowly. The roses do not need to be cut back drastically in fall. Cut back only enough to prevent the canes from whipping in the wind.

Rose cones can also be used, but may require some maintenance as temperatures fluctuate throughout the season. Roses will have to be cut back more severely to fit under a rose cone. Cones should not be put in place until the plants are truly dormant and the soil freezes. Rose cones should be ventilated to prevent heat build up on days when the temperature rises. Remove the cones in spring before new growth begins. If new growth begins under the cone, it may be spindly. Keep cones nearby so they can be easily replaced if the spring weather takes a cold turn.

Winter protection should never be put into place until roses have gone fully dormant. To encourage dormancy, stop deadheading roses around early September and do not make any late applications of fertilizer. Whether you cover your roses with soil or use rose cones, don’t begin the process too soon. Wait until we have had a good, hard frost and the rose is truly dormant.

April - May 2005: Discouraging Canada Geese | Diseases and Insects of Shrubs and Small Trees | Springtime Is Rose Time

 

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