How to prune roses

Prune your roses properly and they will perform better in appreciation. Here’s how to make your first attempt at rose pruning successful to spur the plant’s growth and reap the rewards of more blooms this season.

While there are basic pruning guidelines, such as when to remove dead wood and how to make the right cut, different types of roses often require different approaches to pruning. But for now, let’s answer five frequently asked pruning questions that apply to most roses.

1. When should I prune roses?

In early spring, when red leaf buds on the canes swell and are ready to open, cut back tall canes by one-third their height; the exception is climbing roses anchored to a trellis or wall, where tall growth may be sturdy enough to remain and produce flowering wood.

For “remontant,” or repeat-blooming roses—those that bloom twice or repeatedly in a season—cut spent blossoms and weak, spindly wood immediately after the first flush of blooms is finished in early summer. (If spent flowers are left on the plant, they will form seeds and signal the plant to stop producing new buds.) You can also prune healthy green wood a third time in mid-summer after each flush of flowers is finished, to stimulate more flower-producing wood.

For non-remontant roses (those that bloom once, in early summer), prune immediately after blooming, cutting the canes back by half their length; during summer they will produce new wood to carry next year’s flowers.

To keep ornamental seed cases (“hips”) on plants for display, allow blooms produced in late summer to remain until the hips form.

2. How do I know if wood is dead and when do I remove it?

If it’s obviously brown and brittle, it’s dead wood and should be removed. But sometimes rose canes may have blotchy brown patches and off-colour (pale green) wood that doesn’t look healthy; this may need to be removed, too. In this case, visual inspection is a guessing game—you need to know what the health status is inside the discoloured canes.

First, remove sections of canes that are entirely brown and dead. Then cut into the uppermost section of blotchy, off-colour wood and examine the pith at the interior centre of the cane. It should be milky white, or it may be light beige. But if it’s brown, that section of the cane is dying and should be removed. Cut down the cane in two-inch (5-cm) segments, examining the pith each time, until you reach a section that has milky white or light beige pith. That’s where to stop. When you finish pruning a rose cane, always make the last cut into healthy green wood, leaving no decayed wood on the plant.

Wood that is dead, damaged, diseased, broken, weak or spindly can be cut at any time—you don’t need to wait until spring. However, after winter is the time most dead wood reveals itself. Cutting back healthy green wood in autumn should be limited to overly long canes that might whip around in winter wind and cause damage.

3. Should I cut green, living wood?

Remove weak, spindly green wood that will be pulled down by the weight of flowers.  Follow spindly branches back to where they emerge from and make the cut there. You won’t lose any potential flowers this way, and the energy will be directed toward stronger, thicker wood. Flowers are best supported on wood that’s approximately the diameter of a pencil or larger.

Another time it’s okay to cut green, living wood is when thinning congested canes from the interior of a shrub or climbing rose. This improves air circulation through the plant and discourages fungal diseases. Selectively cutting out canes that cross and rub against each other prevents future abrasive damage and infection.

Most importantly, pruning green canes back after flowering encourages the growth of fresh wood that will carry more flowers this season or next year.

4. What’s the best way to make a pruning cut?

The cut is always made on a 45-degree angle, so rainwater slides off the exposed wood. (A flat, horizontal cut allows water to sit on the exposed wood, encouraging rot in the cane before it can heal over).

Where you decide to cut the cane will influence the direction of new growth. Pruning will activate small red buds on the canes, or ones that are hidden in the leaf axils where they attach to the cane. Select an outward-facing bud or leaflet, so that the new growth will grow outward, and not toward the interior of the plant. Make the slanted cut ¼ inch (6 mm) above the chosen bud, with the top of the cut slanting (or pointing) in the direction the bud will grow. Don’t worry about cutting too much of or too low on a cane when necessary. Healthy, well-nourished roses will make strong new growth after hard pruning.

5. How do I shape a shrub or climbing rose?

Roses with a round, shrubby habit should be shaped to favour strong growth on all sides if there is adequate light. (If light comes primarily from one direction, the shrub will put most of its growth on that side no matter how you prune it.) Select the thickest canes to preserve, and work at pruning the growth to be balanced on each side. Prune out weak interior wood to promote an open centre for air circulation.

Some tall shrubs are more adaptable to training in a fan shape, with tall canes separated and leaning outward in a slight cascade. Be careful to control the weight of flowering canes by cutting out spindly branches so that they aren’t pulled downward when in bloom.

Tall climbing roses over eight feet (2.5 m) should be pruned to three to six permanent canes, spaced out about two feet (60 cm) from each other. Shorten pencil-size side shoots to about six inches (15 cm); remove any twiggy, slender shoots. 

If allowed to grow vertically, the canes on climbing roses will only produce flowers at the top. Training the canes in an arched, horizontal form will greatly increase the number of flowers produced from buds all along the wood. Encourage short climbers, or pillar roses, under six feet (1.8 m) to make flower-bearing side shoots by pruning their tops back by one foot (30 cm) in spring.

Rose-by-rose pruning guide

First, make sure all dead, weak and damaged wood has been removed. Then determine which type of rose you’re pruning, and follow the guidelines below, shaping the plant and directing new growth outward, away from the interior.

Hybrid tea, grandiflora and floribunda roses (e.g., ‘Double Delight’, ‘Queen Elizabeth’, ‘Iceberg’)

Cut canes down to eight to 12 inches (20 to 30 cm) above ground, with three or more buds on each cane. When the first flush of flowers is finished in early summer, cut back the canes by up to half their length to stimulate new wood and flowers. Repeat this process after the second flush is finished to produce early-autumn blossoms.

Hybrid perpetual roses (e.g., ‘Frau Karl Druschki,’ ‘Reine des Violettes’, ‘American Beauty’)

Cut tallest canes back by half their height. Remove flowers when they are finished, and cut back the flowering canes again by one-quarter their height to stimulate further blooms; leaving hybrid perpetual roses unpruned quickly decreases flowering.

Modern shrubs, English roses and Rosa rugosa hybrids (e.g., ‘Adelaide Hoodless’, ‘Jens Munk’, ‘Prairie Joy’, ‘Morden Sunrise’, ‘Charles Austin’, ‘Abraham Darby’, ‘Thérèse Bugnet’, ‘John Cabot’)

Thin congested wood from the interior of shrub and English roses to promote air circulation. Remove one-quarter to one-half the height of the tallest canes. When the first flush of flowers is finished, cut flowering canes back by half their height to stimulate new flower-bearing wood.

Climbing roses, noisette climbers and ramblers (e.g., ‘Alchymist’, ‘New Dawn’, ‘Madame Alfred Carrière’, ‘Bobbie James’)

Leave healthy green wood unpruned for two years as the plants establish their leading canes. In the third spring, cut back length where necessary (when the supporting trellis or arbour is covered). Remove spent flowers immediately after they finish blooming and prune back flowering side shoots by half their length. As the plant ages, remove older canes every second year, cutting them out as low as possible.

Ramblers are more vigorous than climbers, and produce many thin canes. Thin these out to five or six (cutting the others out at the base), so that energy is directed to making side shoots and flowers. Once plants are established, remove old wood every second or third year.

Both climbers and ramblers should have their canes trained and anchored in arched or horizontal directions to promote flower-bearing side shoots all along the canes.

Bourbon and hybrid musk roses (e.g., ‘Zéphirine Drouhin’, ‘Felicia’)

Prune lightly to maintain shape. Hybrid musk roses bloom on both old and new wood; prune two- and three-year-old wood sparingly, and remove four-year-old wood entirely. After each flush, remove spent flowers and lightly cut back tallest branches and longest side shoots, removing one-quarter of their length.

Alba, gallica and centifolia roses (e.g., ‘Queen of Denmark’, ‘Belle Isis’, ‘Juno’)

Short cultivars should be pruned only lightly, removing spent flowers and maintaining shape. Tall roses should have their longest canes cut back by one-quarter. (Old antique roses can grow from two to 10 feet / 60 cm to 3 m in height.) For repeat bloomers, cut back flowering canes by half immediately after blossoms finish to stimulate more flower production.

Damask, Portland and moss roses (e.g., ‘Duc de Cambridge’, ‘Marchesa Boccella’ syn. Jacques Cartier, ‘Etna’)

For repeat-blooming types, in spring cut back the strongest canes to half their length. After flowering, remove spent blooms and cut back the canes by half to stimulate more flowering. For summer-blooming cultivars, don’t prune in spring; remove spent flowers in early summer (leave them if ornamental hips are desired) and cut out canes that are older than three years to stimulate new wood. Tall canes can be shortened to five feet (1.5 m).

Species roses and species hybrids (e.g., Rosa rubrifolia, R. glauca, R. xanthina f. hugonis Hugo’s rose, R. foetida ‘Bicolor’ syn. Austrian Copper rose, R. ‘Geranium’ [moyesii hybrid])

Species roses and their hybrids are tall plants, often with a fountain or cascading form, and can grow 12-foot (3.6-m) canes. Their appearance is most attractive when left unpruned; consequently, they require a large space. To renovate overgrown species shrubs, thin weak wood from the interior. To achieve complete renewal, half the wood can be cut down to the ground over two years.

Bypass is best

When pruning roses, use bypass pruners with sharp blades that slightly pass each other when closed. Anvil pruners, with one sharp blade and one flat blade, are used for cutting dead wood.

To prevent spreading disease from one plant to another, sterilize your pruners when finished with each rose plant by dipping them into a container of equal parts water and liquid chlorine laundry bleach.

 

More on roses

• Roses and Epsom salt
• Putting roses to bed
• How to winterize roses