Rockspray Cotoneaster

Cotoneaster horizontalis

Rosaceae · broadleaf deciduous shrub · introduced

Last updated May 10, 2026

Plant Profile

Size & Form

Height

4 ft

Spread

6-8 ft

Growth Rate

Fast

Size at 20 yr

1 ft

Lifespan

Moderate

Site Requirements

Light

Part Shade

Soil Drainage

Adaptable

Soil pH

5.5–7.0

Water

Moderate

Drought Tolerance

Medium

Hardiness

Zones 4a–8b

Ornamental Interest

Bloom Time

May to June

Fall Color

Red

Origin

Western China

Fire BlightHigh

Bloom Infection Window

AphidHigh

Peak Population & Dispersal

Phytophthora Root RotModerate

Growing Season Stress Expression

Diseases: Regionally Documented (4)

Venturia spp. — multiple host-specific species: V Scab Pseudomonas syringae pv. syringae Bacterial Blight Erwinia amylovora Fire Blight Phytophthora spp. (P Phytophthora Root Rot

Pests: Regionally Documented (3)

Tetranychidae Spider mite Cotoneaster fall-webworm Aphidoidea Aphid

Phenological Calendar

View full calendar (5 stages)

Stage	Typical Window	What to Look For
New growth flush BBCH 11	Feb 15-Mar 15	Lighter-colored new growth visible at branch tips
Bloom start BBCH 61	Mar 15-May 15	First open flowers visible; flowers white
Bloom end / petal fall BBCH 69	Apr 15-May 31	Last petals falling; flower structures fading
Fruit/seed development BBCH 71	Jun 1-Aug 31	Fruit or seed structures forming; fruit color: red
Fruit/seed maturity BBCH 85	Sep 1-Nov 30	Fruit fully colored and ripened; seed dispersal may begin

Data Maturity

Structured Multiple sources. Expert review underway.