Roses are popular garden plants that provide season-long beauty. However, they also require season-long attention. Adequate water during dry periods is essential for continuous bloom. Roses require at least an inch of water per week. A good mulch layer around the plants will help retain soil moisture. Water roses early in the day and avoid wetting the foliage. Black spot, a serious foliage disease of roses, is spread by water splashing on the leaves.
It is important to continually remove spent blooms from roses. This procedure, known as "dead heading" is important to encourage continuous blooming. Spent blooms left on the plant may form seed pods, called hips. Seed pod formation requires a great deal of the plant's energy and slows flower production. To dead-head, remove the flower by making a cut at a 45 degree angle just above a 5-leaflet leaf on the stem. Ideally this should be an outward-facing leaf. Make sure the high side of the diagonal cut is on the side of the stem.
If your roses bloom only once a year, such as some of the shrub or antique roses, remove the spent blooms immediately after they are finished blooming.
Roses can be fertilized in July. This should be the last fertilizer application for the season. Late summer fertilization may stimulate new growth and delay hardening of the wood before winter. Sprinkle 1/4 cup of 5-10-5 or 12-12-12 around each plant and water it in well.
Continue inspecting roses for foliar diseases, such as blackspot and powdery mildew. These fungal diseases can severely defoliate and weaken the plant. Weak plants may suffer considerable winter injury or die. A labelled fungicide, such as Daconil or Funginex, should be applied every 7 to 14 days to insure good protection from blackspot.
This article originally appeared in the July 11, 1997 issue, p. 110.