Roses are easily among the most familiar landscape plants. Ranging greatly in variety, these thorny shrubs are prized for their unique colors and alluring fragrance. While hybrid roses are quite stunning, their lineage can often be traced to another beautiful type of rose, the Rosa rugosa.
I. Appearance and Characteristics
Rosa rugosa (rugosa rose, beach rose, Japanese rose, Ramanas rose, or letchberry) is a species of rose native to eastern Asia, in northeastern China, Japan, Korea and southeastern Siberia, where it grows on beach coasts, often on sand dunes. It should not be confused with Rosa multiflora, which is also known as “Japanese rose”. The Latin word “rugosa” means “wrinkled”, referring to the wrinkled leaves. Often used as an ornamental plant, it has become invasive in parts of Europe, North America and South America.
Rosa rugosa is a suckering shrub which develops new plants from the roots and forms dense thickets 1–1.50 m tall with stems densely covered in numerous short, straight prickles 3–10 mm long. The leaves are 8–15 cm long, pinnate with 5–9 leaflets, most often 7, each leaflet 3–4 cm long, with a distinctly corrugated (rugose, hence the species’ name) surface. The leaf is elliptical in shape with a rounded base or broadly cuneate with a leather feel, dark green top. The back of the leaf is composed of a green-grey colour with hair along the veins.
The leaf margin is composed of teeth along the edges and is crenate-serrate. The flower has five petals that are usually 6–9 cm in width. The flower is composed of 200–250 stamens per flow and vary in style. The flowers are pleasantly scented, dark pink to white (on R. rugosa f. alba (Ware) Rehder), 6–9 cm across, with somewhat wrinkled petals; flowering occurs in spring.
The edible hips, which resemble cherry tomatoes, are large, 2–3 cm diameter, and often shorter than their diameter, not elongated; in late summer and early autumn the plants often bear fruit and flowers at the same time. The leaves typically turn bright yellow before falling in autumn.
This species hybridize readily with many other roses, and is valued by rose breeders for its considerable resistance to the diseases rose rust and rose black spot. It is also extremely tolerant of seaside salt spray and storms, commonly being the first shrub in from the coast. It is widely used in landscaping, being relatively tough and trouble-free. Needing little maintenance due to its being very disease resistant, it is suitable for planting in large numbers; its salt-tolerance makes it useful for planting beside roads which need deicing with salt regularly. It can control erosion.
II. How to Grow and Care
Sunlight
As with most roses, rugosas prefer a spot in full sun, meaning at least six hours of direct sunlight on most days. Too much shade will generally result in fewer blooms.
Temperature
Rugosa rose is widely distributed from cold temperate zones to tropical areas. It likes cool, ventilated environments and is not tolerant of high temperatures. The optimum temperature range is 15 to 26 ℃. Some species can tolerate temperatures as low as -26 ℃ and high temperatures of up to 35 ℃. When the temperature is below 4 ℃ in winter and above 30 ℃ in summer, the plant becomes semi-dormant and has poor growth. The flowers during this period will have a few small, white petals with a dim and lusterless color and are not good-looking at all.
Rugosa rose favors moist conditions but is not resistant to water-logging. It can tolerate moderate drought. Provide more water from budding to flowering, but reduce watering after blooming time. After blooming, wait to water again until the soil is basically dry to avoid any accumulation. Ensure good ventilation and drain excess water during the rainy season to prevent damage to its roots.
Watering
Aim to keep the soil moist but not soggy for young plants. Established shrubs can tolerate some drought, though they still prefer moist soil. Avoid overhead watering, as this can promote fungal growth on the leaves. Likewise, try to water in the morning, so any wet foliage has time to dry in the sunlight. Adding a layer of mulch is also ideal to help retain soil moisture.
Soil
Rugosa rose can adapt to a variety of soil types and grows best in acidic soil which is fertile, loose, and water-drained. When planting in the garden, you should choose a place on higher terrain with sufficient sunlight, good air ventilation, and slightly acidic soil. Planting in high terrain helps avoid water accumulation in soil. Before planting, deeply loosen the soil and use organic fertilizer as base fertilizer. If planting as a potted plant, use humus-rich and slightly acidic sandy soil.
Fertilizing
Unless your soil is very poor, your rugosa roses shouldn’t need a lot of supplemental feeding. A slow-release flowering shrub fertilizer applied in the spring should suffice. For the amount to use, follow the product label instructions.
Planting Instructions
If planting potted rugosa rose in your garden, it’s best to find a suitable site with adequate sunlight, fertile soil, good drainage, and preferably a place that hasn’t been planted with any roses before. A field that previously grew roses may increase the probability of infection. Transplanting can be done in all seasons except winter.
First, dig a pit that is twice as big as the flower pot. Add a small amount of base fertilizer to the pit, and place the root system or root ball into the pit so that the root crown (where the aboveground part and the underground part connect) is at or slightly higher than the surface of the soil. Backfill and slowly compact the soil. A layer of organic mulch can be used to cover the soil surface for heat preservation of roots and also reduce the growth of weeds. Water thoroughly after transplanting and water often in the first week to avoid wilting caused by a lack of water.
If transplanting rugosa rose from one part of the garden to another, do it in fall to avoid the cold of winter. Water the plants three days before transplanting; this makes it easy to dig up and retain the rootballs. Then, trim off the overlong branches and excessive leaves, leaving 3-4 branches per plant to reduce excessive consumption of nutrients and ensure its survival. Prune any unhealthy roots left after being dug up.
If a bare-root rose cannot be immediately planted after purchase, it can simply be placed into a pit and covered with soil. If it has already gone without water for some time, it’s better to soak its roots in water for half an hour before planting to help it recover. It is recommended to plant bare-root roses in gardens in the fall.
Pruning
Rugosa rose has a strong sprouting ability and grows luxuriantly. Without proper, timely pruning, it will attract diseases and pests in hot, humid, insufficiently lit, or poorly ventilated conditions. After the first bloom, the plant should be slightly pruned. Promptly cut off faded flowers and thin, overlapping branches, leaving only young and strong branches. During winter dormancy, careful pruning is recommended.
For vines, keep main branches at 2 to 3 m long and cut off the rest. For bush plants, cut 1.02 cm above full buds, prune the whole plant to 1/3 of its original height, and leave 4-6 thicker branches while ensuring that the overall shape of the plant meets your desired appearance.
Propagation
Rugosa rose can be propagated by grafting. Multiflora rose (Rosa multiflora) is often used as rootstock for grafting. Generally, grafting is carried out from the end of summer to the beginning of autumn, and the grafting part is as close to the ground as possible. Cut a T-shaped cut on the outer skin of the rootstock with a knife on one side of the stem and branch, then select a bud from the middle of a well-developed branch in the same year, cut the bud with bark, insert it into the T-shaped cut, bind it with plastic film, and place it in proper shade. It can usually be untied 15 days after grafting, and will germinate and survive after 30 days.
You can also select a branch that has not yet developed a leaf bud as a scion if the thickness of the scion is more similar to that of the rootstock. Cut a 2 cm deep cut on the rootstock longitudinally, insert the scion into the cut, and then fasten it with plastic film. The incision will heal after about 10 days.
Rugosa rose can also propagate by division. It can be planted deeper and filled with soil to the roots so that new roots can grow at the bottom of each branch. In the early spring or late autumn, the whole plant can be dug out with soil to be divided into ramets. Select a stem with 1-2 branches and some fibrous roots, and then separate it from the whole plant and plant it in a basin or garden. At the same time, prune the branches on the ground to reduce the evaporation of water and improve the survival rate of transplanting.
Cutting propagation, another useful way to propagate rugosa rose, is generally carried out in spring and autumn. Branches with 3-4 buds can be cut off to use. The substrate for cutting can be a mix of river sand, rice chaff ash, or vermiculite, etc. Insert the branches into the substrate, shade it properly, and spray to maintain humidity. The branches will take root 20-30 days after cutting, and the survival rate is 70-80%. If the branches are dipped in rooting powder and then inserted into the substrate, the survival rate will be higher. Additionally, the cuttings can be immersed in water for cutting; the cutting temperature is 20 to 25 ℃, and new roots will grow after 20 days.
Potting and Repotting
Rugosa rose is a shrub rose with a vigorous, suckering growth habit, which does not make it a good choice for container growing. Miniature, patio, and polyantha roses are best for growing in pots.
Overwintering
A layer of mulch around the base of your shrub will help to insulate its roots over the winter. Because these shrubs have excellent cold tolerance, they don’t require any special overwintering maintenance.
Pests and Diseases
Common Pests & Plant Diseases
While rugosa roses generally have very good pest and disease resistance, they still are susceptible to many of the same issues that other rose species face2. Common pests include aphids, scale, rose midges, and leafhoppers. Some infestations can be treated with insecticidal soap or horticultural oil. Common diseases include black spot and powdery mildew. Keeping foliage dry and increasing air circulation will help to prevent disease.
Common Problems
Rugosa roses are typically trouble-free when grown in suitable conditions but heat stress, drought, or overwatering can lead to problems.
Leaves Turning Yellow
If it’s fall, yellow foliage on your rugosa rose might simply be the leaves taking on their natural seasonal color. However, yellow leaves also can be a sign of heat stress, improper watering, or improper soil drainage. Make sure the soil is neither too dry nor too waterlogged.
Drooping Leaves
Leaves drooping or even falling off can often be a sign of lack of moisture. While rugosa roses can tolerate some drought, they do prefer moist soil. And young shrubs especially need consistent watering as their root systems are still developing.
III. Uses and Benefits
- Ornamental uses
The rugosa rose is celebrated as an adaptable and versatile rose suitable for sandy and clay soils and tolerant of poor soils in cottage gardens and along banks. As a specimen plant or in mass, the rugosa rose can be a border plant or offer visual appeal as a flowering hedge as the shrub can grow quite tall. In addition, it is prized for its hardiness and disease resistance. Gardeners can grow the rugosa rose with smokebush, Amethyst sage, or Firetail persicaria.
- Culinary uses
The sweetly scented flowers are traditionally used to make flower jam and dessert in China. They are also used to make pot-pourri in Japan and China. It is used in traditional Chinese medicine to treat irregular menstruation and gastritis. Beach rose hips, like those of other rose species, are edible and can be used to make jams, syrups, tea, or eaten raw.
IV. Harvesting and Storage
Rugosa rose produces excellent fresh flowers that can be pruned with sharp scissors as soon as they bloom. It is best to pick flowers in the morning to avoid loss of water through plant transpiration at noon. After picking, it is necessary to trim the base of the branch at a 45° angle to increase the water absorption area. Quickly put the flower into a vase with clean water to avoid water loss.
