Hybrid tea roses benefit from heavy pruning in winter. Shrub and ground cover roses need only shaping or light shearing. Both techniques are detailed below.
PRUNING HYBRID TEA ROSES
Remove all dead wood and all weak, twiggy branches (darkened in drawing). Make cuts flush with the bud union (the swelling at the base of the plant).
Cut all branches that cross through the center. This opens up the plant and gives it a vase shape. In hot climates, some rosarians just shorten center-crossing branches, so leaves will shade the bud union from the scorching summer sun.
In mild climates, shorten the remaining healthy growth by about one-third.
In cold-winter climates, where freeze damage occurs, remove all dead and injured stems. This may result in a shorter bush.
PRUNING SHRUB ROSES
Remove dead growth and prune old, weak, or diseased canes. Then cut back wayward stems.
If you want to reduce the plant's height and create a bushier form, shear it back by a third to a half.
PRUNING GROUND COVER ROSES
Cut back stems of Flower Carpet and other ground cover roses by about a third of their length. To develop a more prostrate form, cut vertical stems back to the plant's main stem.
Making the proper cuts
Make cuts at a 45° angle about ¼ inch above an outward-facing growth bud. Make a clean cut without ripping the bark. Don't leave stubs.
Always cut above a five-leaflet leaf.
Rose care calendar
The best roses get the best care at the right time. Use this calendar as your guide for what to do when.
Sunset climate zones 4-9, 12-24
• Plant bare-root roses. Ask the nursery to wrap the roots to keep them from drying out, then plant immediately when you get home. (Or temporarily place them on their sides in a shallow trench and cover them with moist sawdust or soil to keep roots from drying out until you can plant them.) Set them in well-drained soil in a spot that gets six to eight hours of sunlight. If soil is sandy or heavy clay, amend it with organic matter such as fir bark or compost.
• Prune plants when temperatures are well above freezing. Prune hybrid teas to a vase shape made from the strongest three to five canes.
• Spray established plants when they're dormant to kill overwintering insects such as aphids and scale and to control diseases such as mildew. Use horticultural oil either alone or mixed with lime sulfur or fixed copper.
Zones 4-9, 12-24
• Finish planting bare-root roses.
• Complete pruning.
• If you haven't already done so, apply dormant sprays to control aphids, black spot, and mildew. Use horticultural oil with lime sulfur or fixed copper.
• In the low desert (zone 13) after midmonth, feed established roses with a complete fertilizer or commercial rose food, following package directions, when buds begin to swell. Water first, let drain, spread the fertilizer around each plant, then water again.
Zones 10-11 (high deserts)
• Plant bare-root roses.
• As soon as buds begin to swell, feed roses with a high-nitrogen fertilizer such as 20-10-10, or a commercial rose food. Continue feeding every four to six weeks until October.
Zones 1-3 (cold climates)
• Plant bare-root roses.
• Prune dormant plants.
• Apply mulch to save water, smother weeds, and keep soil cooler. Spread 1 to 3 inches (depending on size of plant) of bark chips, compost, wood shavings, or other organic material. Leave a circle of bare soil around the plant's base.
• Blast aphids off plants with a jet of water from a hose. If infestations are heavy, spray with insecticidal soap.
• Fertilize roses with high-nitrogen plant food.
• Finish pruning roses.
• Water when rain has been minimal. This is especially important for anything you planted this year and for plants in pots and under house eaves.
• Apply high-nitrogen fertilizer.
• Remove spent flowers. Cut blooms above a five-leaflet leaf.
• Feed, water (especially on hot days), weed, and mulch. Remove faded blooms.
• To eliminate aphids and spider mites from roses, spray plants with water, then apply insecticidal soap.
• Clean up fallen leaves. If they're diseased, discard them (don't compost them).
• Continue removing spent flowers.
• Renew mulch if necessary.
• Feed roses after their fall bloom flush. Use a complete liquid fertilizer at half dose.
• Irrigate plants as needed.
• Continue deadheading and watering.
• Clean up fallen leaves and petals.
• Knock down watering basins.
• Continue deadheading faded flowers.
• Protect plants from winter cold by mounding soil around them. Make sure the soil is high enough to cover the bud union. Then surround each plant with a wire cylinder weighted down at the base with rocks or bricks, and fill in with straw or leaves. Keep protected through winter.
• To control overwintering insects and plant diseases, spray roses this month or next with horticultural oil, oil and lime sulfur, or oil and fixed copper.
• Plant bare-root roses as soon as they appear in the nurseries.
ABOUT THOSE OILS & SOAPS
Insecticidal soap. Mixtures of special fatty acids are of low toxicity to humans but control most small insects and mites. Focus the spray on pest insects to avoid killing beneficial insects.
Horticultural oil. This refined oil smothers insects and their eggs. Use dormant oils during winter to control insects that overwinter on deciduous plants. Apply summer oils after leaves have emerged to control aphids, mites, and the eggs of some insects. Oils can burn sensitive leaves; test a small area first.