How to Plant, Grow, and Care for ‘Iceberg’ Roses

The Rosa genus contains over 150 species of shrub and climbing roses, with numerous cultivars in all sizes and colors. Of those, ‘Iceberg’ is a world favorite, earning the World Federation of Roses Hall of Fame designation. Its endless clusters of pure white blooms free-flower throughout the summer for a crisp, cool, abundant aesthetic.

‘Iceberg’ is a floribunda rose beloved for its beauty, vigor, and reliable performance. The sport of the shrub is an equally stunning climbing selection. Climbing ‘Iceberg’ roses add vertical appeal from near and far. Whether a tidy shrub or an easy-going climber, their easy care and robust repeat blooms enchant the landscape.

What are ‘Iceberg’ Roses?

‘Iceberg’ floribunda rose bears bright white blooms throughout the summer. Clusters of semi-double rosettes free-flower in profusion. With creamy yellow centers and a light honey perfume, pollinators flock to them.

The rose is out of Germany’s acclaimed Kordes Roses. Bred by Reimer Kordes in 1958, it’s a recipient of the Royal Horticultural Society’s Award of Garden Merit for its non stop flowering and hardy stock. It thrives with a bit of neglect and is tolerant of dappled light and less-than-ideal conditions.

The accolades for ‘Iceberg’ are almost as numerous as its endless blossoms. It won the National Rose Society’s Gold Medal in 1958 and World’s Favorite Rose in 1983.

These floribundas make a lovely show in small groups, mixed borders, and foundation plantings. They’re ideal in cottage and cutting gardens, fragrance-themed arrangements, and large containers.

The climbing ‘Iceberg’ rose grows quickly with long, pliable stems that train easily. It, too, features continual flowering, attractive foliage, and easy-care growing. The floriferous stems quickly fill large trellises, house walls, arbors, pillars, arches, and fences. Unlike other climbing vines, they don’t twine naturally. They need support, training, and tying to a sturdy structure to climb.

Without upright support, the climbers grow as free-standing shrubs. Let them ramble down a slope, crawl along a wall, or make graceful, arching garden specimens.

Characteristics

‘Iceberg’ roses cool the summer display with sprays of medium-sized, semi-double white flowers. These showy clusters have 15 rosettes per bundle. 

While primarily shades of white, petal tips may have a pale pink blush. Flowers measure three inches across and hold up to 25 petals. Yellow stamens appear as flowers open fully.

The shrubs grow three to five feet tall and wide and have an upright habit. Plants have handsome, glossy foliage in medium green. Stems have few thorns.

New genetically mutated shoots are called sports, and they differ from the shrubby base branches. A climbing sport on this rose can grow up to 15 feet tall. After flowering, buds develop on old wood (the previous season’s growth).

Both the shrub and the sport are cold-hardy and disease-resistant. They tolerate partial shade.

Native Area

Floribunda roses arose from crossing a hybrid tea with a polyantha. Since floribundas are further hybrids, they’re of cultivated origin. Their ancestors date back to wild species native to Asia, particularly China.

Polyanthas are rugged and vigorous growers. They produce clusters of small blooms and repeatedly blossom on upright shrub forms. Hybrid teas have lineage in old garden selections, leading to their florist-worthy pointed buds and stylized blooms.

Rosa ‘Iceberg’ is a cross between R. ‘Robin Hood’ and R. ‘Virgo.’ ‘Robin Hood’ is a Pemberton-bred 1927 hybrid musk with repeat clusters of small, cherry red flowers with white centers. Joseph Pemberton is a renowned British rosarian who created the first hybrid musks. His sister introduced ‘Robin Hood’ after his death the year before. The original, ancient musk roses have roots in southern Europe and the Middle East.

‘Robin Hood’ boasts good disease resistance and shade tolerance. The strong shrubs have an upright habit and reach four to five feet tall. ‘Robin Hood’ is an easy grower and adapts to various soil types.

‘Virgo’ is a short hybrid tea rose introduced by Charles Mallerin in Meilland, France, in 1947. High-pointed buds on long stems open to scrolled double blooms in white shades. The lightly scented teas occur from summer through fall.

The climbing ‘Iceberg’ came about as a sport, or genetic mutation of the floribunda, resulting in an offshoot. Breeders cultivate these offshoots for the traits of the parent plant in climbing form.

Planting

For good air circulation and to plan for maturity, leave ample space around the plant for air movement. Plenty of space gives roots and upper growth enough room to spread. Leave at least one foot between roses and companion plantings and three to four feet between larger plants to avoid overcrowding.

If your plant is a climber, place it near a support structure like a pillar, wall, arbor, or trellis. In their second year, long canes develop. Tie these to your support structure to direct growth.

Transplanting 

Roses can be planted year-round, with the best conditions generally in late winter, early spring, and fall. Cool temperatures and seasonal moisture allow the plant to settle in stress-free. Avoid planting in frozen or waterlogged conditions and extreme heat or drought.

Plants arrive potted or bare-root. Bare root roses are dormant and without potting soil. They quickly flush out after planting as temperatures warm. They’ll establish over the spring for summer blooming.

Dig a hole six to eight inches larger than the root ball to comfortably accommodate all roots and loosen the surrounding soil. For both nursery potted and bare-root plants, amend the native soil with compost.

How to Grow

This durable selection is a carefree rose that does not require fussy maintenance. However, all roses benefit from certain growing conditions for optimal health and flowering.

Ensuring air circulation for vigor and health while preventing foliar diseases is essential to growing healthy plants.

For climbers, long canes train easily on upright structures. Since canes don’t twine independently, they’ll continue to need tying off as they grow. The stunning reward is worth the effort.

Light

‘Iceberg’ rose shrubs grow best in full sun, where blooming and disease resistance improve. They also grow in partial shade. A good rule of thumb for shaded roses is at least four hours of sun. Dappled sunlight is fine for this tough hybrid, but increased shade decreases flowering and overall health. 

In hot summer climates, they’ll benefit from the morning sun with protection from direct afternoon rays.

Water

Once established, ‘Iceberg’ roses are somewhat drought-tolerant, but they’ll appreciate about one inch of water per week during dry spells. They may need more soil moisture during heat waves or prolonged drought. Water deeply when soils are dry to a depth of one inch. 

When newly planted, ensure the surrounding soil stays moist. Once established, water needs are average, with regular rainfall plus supplemental irrigation during dry conditions. Watering too frequently increases the likelihood of pests and fungal diseases.

All roses do best with morning water, preferably drip or ground-level irrigation. Avoiding overhead watering helps prevent foliar diseases, especially by avoiding evening or nighttime sprinklers. Some gardeners do fine with overhead irrigation for roses, watering in the morning to give leaves time to dry in the sun.

Soil

The ‘Iceberg’ rose prefers loose, rich, slightly acidic soils with a pH between 5.5 and 6.5. They thrive in well-draining soils with even moisture.

Add three to six inches of compost from completely broken-down plant material at planting. Compost helps with aeration, moisture retention, drainage, and nutrition. 

Temperature and Humidity

This species is hardy down to USDA zone 5 and up to zone 9. For planting, they’ll prefer temperatures between 40 and 60°F (4-16°C).

Mulch around plants to help regulate temperatures, keeping roots cool in the summer and providing insulation in the winter. In cold winter areas, protect the crowns for best overwintering.

In areas with high humidity, provide plenty of air circulation. Avoid overcrowding with other plants.

Fertilizing

A balanced fertilizer in early spring and early summer ensures a vital growing season. Fish emulsion, seaweed extract, or an organic rose-specific fertilizer do the trick. Mycorrhizal fungi promote healthy roots and soil.

Maintenance

While low-maintenance, ‘Iceberg’ roses benefit from a few seasonal garden tasks for overall health. Maintain a three-inch layer of mulch year-round to retain moisture, regulate temperature, and suppress weeds. Mulch also adds nutrients to the soil as it decomposes.

Remove spent flowers to encourage reblooming. Floribundas free-flower all season (even without deadheading) but produce more quickly when not directing energy to seed.

Remove diseased leaves and those from the ground as part of regular maintenance. Removing fallen leaves and flowers promotes overall health and reduces the occurrence of pests and diseases.

Prune floribundas in late winter and early spring. Reduce established plants by one-third to maintain the current size in the growing season. They’ll take heavy pruning. Cut them back within 18 inches of the ground for rejuvenation. Aim for a rounded form for the best aesthetic.

For climbing types, prune for shape in the fall before spring buds set. Train them periodically in the season. As preventative maintenance, remove crossed, diseased, or dead canes at any time of year.

Propagation

‘Iceberg’ roses propagate readily through hardwood cuttings. Although the cuttings may take a few years to develop into full, multi-stemmed plants, reproducing the parent plant through cuttings is relatively easy.

Cuttings

Propagate ‘Iceberg’ rose from cuttings in the spring or fall. Take multiple cuttings since not all may root.

Popular Varieties

The original ‘Iceberg’ rose is the parent to durable offspring. Further cultivars yield pink and deep purple-red flowers in the same vigorous forms. Pollinators enjoy their open centers.

Rosa ‘Brilliant Pink Iceberg’

Rosa ‘PRObil,’ or ‘Brilliant Pink,’ is a mutation of ‘Blushing Pink Iceberg,’ a soft pink-blooming version of the original from Lilia Weatherly of Tasmania rose. ‘Brilliant Pink’ features deeper pink shades, with more intense coloring in cooler climates. 

‘Brilliant Pink’ has lilac-pink petals with creamy pink reverses. Bushy plants grow two and a half to five feet tall and wide. Their more diminutive stature makes them well-suited to containers and the rose border. ‘Brilliant Pink’ is heat tolerant with good resistance like its parent.

Rosa ‘Burgundy Iceberg’

Rosa ‘PROse’ bears four-inch semi-double flowers in purple and burgundy. Light reverses provide a striking contrast to the uniquely dark petals.

‘Burgundy’ is a color mutation of ‘Brilliant Pink,’ discovered by Edgar Norman Swane in Australia. Plants bloom continuously and are darkest in cool temperatures. They’re hardy in zones 6-10. They reach three to five feet tall and wide with dense foliage and rounded forms. 

Common Problems

Choosing a disease-resistant plant and providing the appropriate cultural conditions are the first steps to healthy and beautiful ‘Iceberg’ roses.

While ‘Iceberg’ has good disease resistance, they’re still susceptible to black spot, powdery mildew, and rosette disease. Aphids, beetles, scale, and spider mites may be occasional problems. 

Planting in full sun with plenty of air circulation and average moisture helps stave off infections. Pruning and removing diseased leaves helps prevent the spread of pests and diseases. 

Certain companion plantings, like lavender, catmint, allium, geranium, and agastache, help repel pests like aphids, beetles, and mites. They’ll also attract beneficial insects, creating a well-rounded garden system.

Pests

The best way to control insects is to spot them early. You’ll likely see the insects themselves, or you’ll notice their sticky waste on plants (aphids), their nibble damage to leaves (beetles), or their webbing and yellowing of leaves (mites).

Aphids are common garden insects usually treated with non-chemical means. Often, they cause no damage, but severe infestations cause stress. Signs include curled leaves and stunted growth. Spray them with a strong stream of water from a hose. Follow up with neem if necessary.

Scale pierce leaves and stems to feed on sap. The little legless blobs usually appear on the undersides of leaves and stems as black, gray, or silvery dots. Leaves may yellow and drop, with branches dying back in heavy infestations. Remove affected plant parts in severe infestations. Pop small population off the plant with a cotton swab soaked in 70% or less alcohol.

Mites live on the undersides of leaves, indicated by webbing and light yellowing of leaf surfaces. Beneficial insects like ladybugs and predatory mites help control populations. Spray them with a stream of water from a hose. It’s important to ensure mites don’t take hold of your roses, as some are vectors for deadly rosette virus.

Japanese beetles feed on leaves, causing them to turn yellow and drop. In some cases, they’ll skeletonize foliage. Hand-pick them off your plants as they feed. Treat soil where they’re known to be active with two treatments of beneficial nematodes spaced two weeks apart in temperate seasons.

Diseases

As with pests, the best disease control is prevention through cultural conditions. In general, it’s best to remove problem roses from the garden to minimize chemical treatments and promote the health of surrounding plants.

Powdery mildew is a common fungal disease indicated by a gray-white powdery substance on leaves, stems, and buds. Leaves may distort and drop. Prune appropriate and remove any powdery foliage as you notice it to prevent the spread of this fungal disease.

Black spot fungus carries black spots with feathery margins on leaves and stems. Black spot occurs when leaves remain overly wet from overhead watering or periods of prolonged moisture. If spraying leaves with water to deter pests, do so in the morning or midday when leaves will have time to dry in the sun. Remove damaged foliage as it crops up.

Horticultural oils like neem treat black spot and powdery mildew (but again, these impact beneficial insects, so be sure to follow application requirements).

Rosette virus is a deadly disease that causes distorted growth in roses. New leaves will remain red, and stems take on an excessively thorny appearance. Control mites to limit the spread of this disease. Remove any rose bushes that contract rosette and burn them.