Yak Rhododendron

Rhododendron yakushimanum

Ericaceae · broadleaf evergreen shrub · introduced

Last updated March 8, 2026

Data Maturity Structured

This profile synthesizes data from multiple published sources. Expert field review is in progress.

Yak rhododendron (Rhododendron yakushimanum) is a compact broadleaf evergreen shrub in the Ericaceae family native to Yaku-shima Island, Japan. It reaches 1-4 ft tall and produces bell-shaped flowers 3-4 cm across, rose in bud opening to white, with approximately 10 flowers per cluster. It blooms on previous season's wood and is cold-hardy to 25F.

Yak rhododendron has 35 diseases and 21 pests documented in managed landscapes. All parts are poisonous to humans, cats, dogs, and horses. Its compact habit and attractive flower progression from rose bud to white bloom make it a valued specimen among dwarf rhododendrons.

Quick Facts

Height

1–4 ft

Hardiness

Zone Zone 25F

Origin

the Yaku-shima Island, Japan

Diseases (22)

Root Rot (Phytophthora spp.) Multiple obligate biotrophic fungi (Erysiphales: Erysipha... Powdery Mildew Ovulinia azaleae Ovulinia Petal Blight Lime-induced Chlorosis Symptom category — not a single disease Leaf Spot Exobasidium vaccinii Leaf and Flower Gall Cylindrocladium scoparium Cylindrocladium Blight and Root Rot Botrytis Petal Blight Xylella fastidiosa Marginal leaf necrosis Rhododendron and Cutting Rots Leaf Burn abiotic (drought, heat stress) or bacterial (Xylella fast... Leaf Scorch Ramorum Blight (Sudden Oak Death) Botryosphaeria dothidea Botryosphaeria Dieback Seifertia azaleae Bud Blight Rhododendron necrotic ringspot virus Necrotic Ringspot Thekopsora minima and Naohidemyces vaccinii Rust Taphrina wiesneri Witches' Broom Armillaria ostoyae Armillaria Root Rot Pestalotiopsis sydowiana Gray Blight Physiological leaf spot Phytophthora Blight

Pests (21)

Tetranychidae Spider mite Otiorhynchus spp. Root weevil Choristoneura rosaceana Obliquebanded Leafroller Caloptilia azaleella Azalea leafminer Stephanitis pyrioides Azalea Lace Bug Acanthococcus azaleae Azalea bark scale Salt injury Sunburn Tissue Proliferation Aphidoidea Aphid Lepidoptera Caterpillars Parthenolecanium spp. Lecanium scale Stephanitis rhododendri Rhododendron lace bug Dialeurodes chittendeni Rhododendron whitefly Nematus lipovskyi Azalea sawfly Tingidae Lace bug Stephanitis spp. Azalea and rhododendron lace bug Cacoecimorpha pronubana Carnation tortrix Icerya purchasi Cottony cushion scale Coleotechnites huntella Rhododendron bud moth Nematode, Stunt

Cultivars (2)

'Yaku Princess'

'Ken Janeck'