Rockspray cotoneaster (Cotoneaster horizontalis) is a low-growing deciduous shrub that makes a colorful accent to your garden. Showy pale pink flowers blossom spring to summer with bright scarlet fruit appearing in late summer to early fall. Glossy dark green leaves turn reddish-purple in fall. Attracts butterflies and birds grows to 30 to 61 cm tall in full sun to partial shade.
I. Appearance and Characteristics
Cotoneaster horizontalis is a species of flowering plant in the genus Cotoneaster of the family Rosaceae.
Cotoneaster horizontalis is a short shrub with a spreading habit, growing to 1 metre (3 ft 3 in) tall by 1.5 metres (4 ft 11 in) wide. It is cultivated for its flat, symmetrical sprays of glossy green, deciduous leaves 6 to 12 mm long. The flowers appear in summer, and can range from pink to white. It is commonly grown in parks and gardens in temperate regions as hedging or groundcover.

Cotoneaster horizontalis is native to mountains of Nepal, China, and Taiwan; in China it occurs from Tibet and Yunnan in the west to Jiangsu and Zhejiang in the east and is absent from the north and the very south. It has naturalised in parts of the United Kingdom, and may be becoming invasive. It has been recorded from Counties Down, Antrim and Dublin in Ireland.
This plant has gained the Royal Horticultural Society’s Award of Garden Merit.
II. How to Grow and Care
Sunlight
Give rockspray cotoneaster full sun for optimal berry production and fall foliage color.
Temperature and Humidity
These plants struggle in hot conditions, so don’t try to grow them south of zone 7. These plants do well in relatively low humidity; humid weather may cause fungal leaf spots, though this is rarely a life-threatening problem.
Watering

Rock cotoneaster is a drought-tolerant shrub once established. But until it is established, water regularly to keep its soil evenly moist.
Soil
This plant is not fussy about soil pH, although it generally performs best in soil with a roughly neutral pH. Its main soil requirement is good drainage. A loamy soil works best.
Fertilizing
Rock cotoneaster is not a heavy feeder. Add compost to the soil as needed.
Pruning
It is not necessary to prune cotoneaster plants for their health, but you may want to do so in the spring to contain their spread. And if you do prune them, don’t trim off the stem tips, as this will ruin the naturally graceful shape. If you feel that a particular branch spoils the overall shape of the plant, follow the branch back to the center of the shrub and make your pruning cut there.
Rockspray cotoneaster is the type of bush that will strike down roots wherever one of its branches touches the ground. This enables it to spread fairly rapidly. If this is an undesirable trait for you, then you’ll need to keep up with your pruning to restrict the bush’s spread. If low-maintenance landscaping is a priority for you, you may wish to skip rockspray cotoneaster altogether and grow a less aggressive plant.
Propagation

The easiest way to propagate this plant is by stem cuttings. Take these easy steps:
- In July or August, cut away some of the plant’s healthy side shoots, cutting just below a leaf node. Remove the lower leaves.
- Plant the cuttings into a gritty potting medium.
- Cover the pot with a clear plastic bag or dome, and place it in a bright location.
- When new shoots begin to appear, remove the cover and continue to grow indoors.
- By the following spring, the new specimen will have a good root system and will be ready to be planted in the landscape.
- Choose a permanent spot for your shrub when transplanting the young plant.
Growing Rockspray Cotoneaster From Seed
Growing this plant from seeds is a bit of a process. Take these steps:
- Rough up the outer shell of the seeds by using sandpaper or by rubbing them in your hands with some sand. This is best done in the fall.
- The seeds then need to be cold-stratified. Do this by placing them in a plastic bag along with some moist peat or vermiculite and storing the bag in the refrigerator for 3 to 4 months, or until the seeds sprout.
- Once the seeds have sprouted, they can be placed in small pots filled with loamy soil.
- Set the pots in a bright location where the temperature will hover around 75 degrees Fahrenheit. Keep the soil moist.
- When the plants are about 1 inch tall begin putting the pot outdoors for progressively longer periods each day. After the plants can withstand around five hours of sunlight without wilting, place them in the ground in a permanent spot, spacing plants about 10 feet apart.
Overwintering
Aside from mulching around your plant before the temperatures get too low, rockspray cotoneaster do not require any special treatment during the winter months.

Pests and Diseases
Common Pests & Plant Diseases
There are no serious insect or disease issues with rockspray cotoneaster, but it can be susceptible to some of the same problems that afflict other members of the rose family.
Spider mites and other types of mites can show up during hot dry summers, but they can usually be handled with regular blasting with water from a strong hose. The most serious insect pest is the cotoneaster webworm, which can skeletonize the leaves. Webs will be visible on leaves and branches. These pests are difficult to control, and usually require the application of a chemical pesticide.
Fire blight, leaf spots, and cankers may be problems. Branches showing signs of fire blight or canker should be removed and destroyed. Leaf spots may require treatment with a garden fungicide if the symptoms are severe.
Common Problems
Rockspray cotoneaster is an easy plant to grow and once established, it will survive and thrive largely on its own, provided it doesn’t suffer prolonged drought. But there are a few problems to be on the lookout for, including the following.
- Browning Foliage and Branches
If the ends of the twigs or branches appear to look “tinged” by fire, and dead leaves and flowers are still attached, the plant is suffering from fire blight, a bacterial disease. You may also see oozing cankers. If only some parts of the shrub are affected, prune out diseased parts, disinfecting the pruning tool after each cut. If the entire shrub is dead, dig it out and discard. However, C. horizontalis is one of the types of this plant that is a bit more resistant to fire blight.4
- Yellowing Foliage
If the undersides of the plant’s leaves are yellowing, there’s likely a spider mite infestation that requires insecticidal soap.
- Branch Dieback
Pests, such as scale, can feed on the sap of branches which can cause death to the branches and then the entire shrub. Control scale with horticultural oil. Branches that are dying back and are covered in pimple growths and structures could be affected by Botryosphaeria canker, The shrub could be under stress from excess drought. Prune infected parts.
- Blistering
Yellowish or reddish-brown blistering on leaves can indicate microscopic blister mites (Phytoputus pyri) and requires horticultural oil.
III. Uses and Benefits

Rockspray cotoneaster is a commonly grown compact shrub grown for its cheery summer fruits and dazzling orange fall foliage. This delightful plant may be used for hedging, screening, as a groundcover, or for cascading down fences and walls. Rockspray cotoneaster is perfect in cottage-style and informal gardens or simply wherever you need a pop of color, for this plant is very versatile. Juniper makes for a wonderful contrast.