IDENTIFY
Rhododendron / Azalea identification guide
If you don't know your plant's name, these questions get you to the right group in most cases. Unlike Clematis pruning groups, none of these three need much pruning at all — the real risk of guessing wrong here is about winter hardiness and eventual size, not pruning damage.
- 1
Does it lose all its leaves and stand bare over winter?
YesOften with good red/orange/gold autumn colour beforehand, and typically scented flowers in May — a trait essentially absent in the evergreen groups.→ Deciduous azalea ›No, it stays leafy year-round→ question 2 - 2
How big and woody is it — a bulky, rounded bush over about 1.5m on a few thick stems, or a smaller, twiggier dome under about 1.2m on many thin stems?
Big, thick-stemmed, over 1.5m→ Rhododendron ›Small, twiggy, under 1.2m→ Evergreen azalea ›Not sure / young plant, size unclear→ question 3 - 3
Look closely at the leaves and flowers: are the leaves large, leathery and glossy with big bell-shaped flowers in a tight rounded cluster, or smaller and narrower with smaller, more open funnel-shaped flowers?
Large leathery leaves, big bell flowers in dense clusters→ Rhododendron ›Smaller narrower leaves, smaller funnel flowers→ Evergreen azalea ›
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If you are still unsure
If you genuinely can't tell rhododendron_evergreen from azalea_evergreen, treat it cautiously as the less-hardy azalea_evergreen group for winter protection purposes — mulch the root area and avoid an exposed frost pocket. Over-protecting a hardy plant costs nothing; under-protecting a tender one can kill it.
COMMON MISTAKE
Mistaking a less-hardy evergreen azalea for a large, hardy rhododendron (or vice versa) and assuming the same winter protection needs. Evergreen azaleas (H4-H5) are noticeably more cold-sensitive than the bulkier hardy rhododendrons and hardy deciduous azaleas (both H5-H6) they can superficially resemble at a glance — a plant left unprotected on that wrong assumption can be lost in a hard winter that the other two groups shrug off.
Already know the variety name?
The name on the label tells you the type.
Rhododendron ponticumRhododendron › · Purple funnel-shaped flowers, densely branched, 2.5-4m; the wild-naturalised species seen in woodland across the UK.
Rhododendron ‘Nova Zembla’Rhododendron › · Dark bluish-red, spotted throat, one of the hardiest hybrids sold.
Rhododendron ‘Cunningham’s White'Rhododendron › · Pink buds opening to white, very tough and tolerant, often used as a rootstock.
Rhododendron ‘Percy Wiseman’Rhododendron › · Pink-flushed cream fading to creamy-white, glossy dark green foliage, RHS Award of Garden Merit.
Rhododendron ‘Gomer Waterer’Rhododendron › · Blush white with a yellow flare, flowers later than most, 1.5-1.8m.
Rhododendron ‘Anna Rose Whitney’Rhododendron › · Deep pink with brown spotting, vigorous and large-growing.
Rhododendron ‘Markeeta’s Prize'Rhododendron › · Bright scarlet with darker spots on the upper petal.
Rhododendron ‘Fastuosum Flore Pleno’Rhododendron › · Fully double lilac-purple flowers, a distinctive doubled form.
Rhododendron ‘Christmas Cheer’Rhododendron › · Unusually early flowering window, pink fading to blush, compact for the group at 0.9-1.2m.
Rhododendron ‘Marcel Menard’Rhododendron › · Deep violet-purple, mid-season.
Rhododendron ponticum ‘Variegatum’Rhododendron › · Lilac flowers, but the real giveaway is the silver-variegated leaf margin — useful when it isn't in flower.
Rhododendron ‘Virginia Richards’Rhododendron › · Pink opening flowers fading to yellow as they age, an unusual two-tone effect on the same truss.
Rhododendron ‘Hino-crimson’Evergreen azalea › · Bright crimson, small funnel flowers, classic compact Kurume-type evergreen azalea; good bronze-red winter leaf colour.
Rhododendron ‘Kirin’Evergreen azalea › · Soft salmon-pink, semi-double, hose-in-hose flowers (one flower nested inside another).
Rhododendron ‘Kure-no-yuki’Evergreen azalea › · White-flowered Kurume type, small and neat.
Rhododendron ‘Amoena’Evergreen azalea › · Magenta-purple, small hose-in-hose flowers, one of the oldest and hardiest evergreen azaleas grown.
Rhododendron ‘Mother’s Day'Evergreen azalea › · Bright red, semi-double, the most widely sold pot azalea in UK supermarkets and garden centres.
Rhododendron ‘Blaauw’s Pink'Evergreen azalea › · Double salmon-pink, compact 50-75cm.
Rhododendron ‘Gaiety’Evergreen azalea › · Pale pink with a darker blotch, compact 60-80cm.
Rhododendron ‘Mary Helen’Evergreen azalea › · White with a yellow throat, compact 50-75cm.
Rhododendron ‘Geisha Purple’Evergreen azalea › · Reddish-purple, very compact at 40-60cm, good for a pot.
Rhododendron ‘Mount Seven Star’Evergreen azalea › · Low, wide, prostrate habit (30-40cm) and later-flowering than most evergreen azaleas — brick-red flowers; useful outlier if the plant looks unusually flat and spreading.
Rhododendron luteumDeciduous azalea › · Pale yellow, strongly fragrant, good orange-red autumn leaf colour; the classic wild parent species behind many deciduous azalea hybrids.
Rhododendron ‘Gibraltar’Deciduous azalea › · Rich flame-orange with a yellow flare, frilled petals, no scent — one of the most widely sold deciduous azaleas.
Rhododendron ‘Cecile’Deciduous azalea › · Salmon-pink with a yellow flare, a classic Exbury hybrid.
Rhododendron ‘Persil’Deciduous azalea › · Pure white with a deep yellow flare, mid-late season.
Rhododendron ‘Klondyke’Deciduous azalea › · Bright golden yellow, coppery-red buds and new growth.
Rhododendron ‘Silver Slipper’Deciduous azalea › · White with a yellow-orange flare, large flowers, coppery autumn foliage.
Rhododendron ‘Homebush’Deciduous azalea › · Deep carmine-pink, fully double, ball-shaped truss with no visible stamens — very distinctive.
Rhododendron ‘Daviesii’Deciduous azalea › · Creamy white with a yellow blotch, pink-tinged buds, scented, an old Ghent hybrid.
Rhododendron ‘Narcissiflorum’Deciduous azalea › · Pale yellow, double, small honeysuckle-like flowers, strongly scented — one of the most fragrant deciduous azaleas.
Rhododendron ‘Strawberry Ice’Deciduous azalea › · Deep-to-mid pink with a golden flare, bronzy young growth, a very popular UK garden-centre variety.