How to Grow a Pierre de Ronsard Rose

Sun

Full sun produces the heaviest bloom, with six or more hours of direct light each day as the minimum. Less light gives a leafy plant with sparse flowers and more disease pressure.

In the hottest zones, a few hours of afternoon shade keeps the pink blooms from bleaching out and protects the foliage from heat scorch.

Drainage

Well-drained soil is essential. Soggy soil rots the roots and invites disease. Dig a one-foot test hole and fill it with water. If water drains within a few hours, the spot is fine. If water sits, build a raised mound 8 to 12 inches above grade.

Soil

Rich loamy soil amended with compost is the natural preference. Work a few inches of compost into the planting area before setting the plant. The soil should hold moisture between waterings without staying soggy.

Space and the support

Give the plant at least 6 to 8 feet of clear horizontal space along the support, and pick a structure that can hold a heavy mature climbing rose. A wall with sturdy wire mesh, a thick wooden arbor, or a heavy metal pillar all work well. Thin trellises bow under the weight of a mature plant.

Plant the rose about 12 inches out from a wall or fence to allow airflow behind the canes.

Watering

Water deeply once a week through the first growing season, soaking the root zone rather than the leaves. Wet foliage invites black spot. Drip irrigation or a soaker hose at the base works best.

After the first year, water deeply every 7 to 10 days through summer, more often in extended heat. An established plant in rich mulched soil pulls through short dry spells, but consistent moisture produces the best bloom.

Feeding

Feed three times through the season. The first feeding goes in early spring as new growth pushes, the second after the first major bloom flush, and the third in midsummer. Use a balanced rose fertilizer or a slow-release formula labeled for blooming plants.

Stop feeding by early August so new growth hardens off before winter. Late nitrogen produces soft growth that dies back in cold weather.

Late winter pruning

Prune in late winter while the plant is still dormant, just as the buds begin to swell. Cut out any dead, broken, or crossing canes at the base. Trim side shoots back to 2 to 3 buds, which is where the spring bloom forms. Leave the main long canes alone except to remove the oldest tired ones at the base.

Training the canes

Bending the long canes horizontally along the support tricks the plant into pushing flowering shoots all along the cane. Vertical canes bloom only at the tips. Tie new canes loosely to the support with soft garden twine as they grow, weaving them across the wall, arbor, or pillar.

Loosen and re-tie ties each year to prevent the twine cutting into the thickening canes.

Deadheading

Snip spent flowers off through the season to keep the plant tidy and encourage repeat bloom. Cut back to the first set of healthy five-leaflet leaves below the bloom cluster. Stop deadheading in late summer to let the plant set hips and prepare for winter.

Renovating an overgrown plant

If the plant has become a thicket of woody bare canes, renovate over three years. Each late winter, remove a third of the oldest canes at the base. New canes push from the crown to replace them. By year three the plant has a fresh framework without ever losing a season of bloom.

Bloom timing

The first heavy flush opens in late spring, usually May or June depending on the zone. After the first flush fades, the plant reblooms lightly through summer and into fall, with a second smaller flush in early fall in many climates. The first flush is the showstopper.

Cutting for arrangements

Cut blooms in the morning when the petals are tight to half-open. Cut just above a set of healthy five-leaflet leaves to encourage rebloom. Strip the lower leaves before placing in water. Stems hold 5 to 7 days in a clean vase with fresh water and a sugar-vinegar preservative.

Fall hips and winter dormancy

If a few last blooms are left in early fall, the plant sets small orange-red hips that hold through winter and feed birds. Hips also signal the plant to harden off for cold weather, so stop deadheading in late summer to encourage them.

Black spots on leaves

Black spot fungus, the most common rose disease. Dark spots ringed with yellow appear on the leaves, often spreading from the bottom of the plant up. Pick off affected leaves and discard them in the trash, not the compost. Water at the base rather than overhead, mulch to prevent soil splash, and apply a fungicide labeled for black spot during humid weather.

Aphids on new growth

Small green or pink insects clustered on tender new shoots and buds in spring. Knock them off with a strong spray of water every few days. Heavy infestations respond to insecticidal soap. Ladybugs and lacewings clear aphids faster than any spray, so avoid broad pesticides that kill them too.

Powdery mildew

White powdery film on the leaves and new growth, especially in humid weather with poor airflow. Thin crowded canes during winter pruning to improve airflow. A horticultural oil or potassium bicarbonate spray controls heavy outbreaks. Avoid overhead watering.

Japanese beetles eating flowers and leaves

Metallic green beetles chewing ragged holes in petals and leaves in early to mid summer. Knock beetles into a bucket of soapy water in the cool morning when they are sluggish. Avoid pheromone traps, which attract more beetles than they catch. Heavy populations may need a labeled spray during peak flight.

Yellowing leaves with green veins

Iron chlorosis from alkaline soil. Apply a chelated iron foliar spray for quick green-up and amend the soil with a fertilizer labeled for acid-loving plants. A long-term shift to slightly acidic soil takes a season or two.

Rose rosette disease

A serious viral disease showing as deformed red witch's-broom growth on a cane. There is no cure. Dig and destroy the entire affected plant including the roots to prevent spread to nearby roses. Do not replant a rose in the same spot for at least 2 years.

Cane borers

Small holes in cut cane tips with a tunnel inside the stem, sometimes with wilting tip growth. Cut affected canes back to clean white pith and seal the cut with a dab of white glue or pruning paste. Most affected plants outgrow the damage without intervention.

Sparse bloom

Usually too little sun, vertical untrained canes, or hard pruning that removed flowering wood. Move to a sunnier spot if possible, train new canes horizontally along the support, and stop hard-pruning the long canes. Feed lightly to support steady growth.

Winter dieback at the cold edge of the range

Stem tips die back at zone 5 sites in cold winters. Mound 6 to 8 inches of soil or mulch over the base of the plant in late fall to protect the graft union. Wait until new growth pushes in late spring before cutting damaged canes back to the lowest green bud.