Use with caution
All parts of azaleas and rhododendrons are seriously toxic - they contain grayanotoxins that can cause drooling, vomiting, weakness, an abnormal heartbeat, and even coma in dogs, cats, and horses, and they are poisonous to people too (even honey made from the flowers can be toxic). Plant where pets and children will not graze it, and never eat any part.
Karen Azalea
Rhododendron 'Karen'
flowerKaren is one of the hardiest evergreen azaleas, a Gable hybrid bred in Pennsylvania for gardens too cold for most evergreen types. It forms a dense, rounded mound three to four feet tall and wide of small glossy olive-green leaves that take on coppery tones through winter, and in mid to late spring it disappears under masses of open, funnel-shaped, lavender-purple flowers about two inches across. Azaleas are shallow-rooted woodland shrubs that thrive in the dappled light and acid, humus-rich soil beneath high trees, and Karen is a reliable choice for foundation plantings, shrub borders, and woodland edges in zones 5 to 8 where harder cold would kill lesser azaleas.
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Sun
partial shade
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Water
Every 7 days
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Bloom
~25 days
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Difficulty
medium
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Lifecycle
perennial
Comes back every year
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Spacing
3-4 ft apart
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Planting Depth
Plant shallow, top of root ball slightly above grade; mulch but keep mulch off the stem
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Soil pH
4.5-6.0
Growing Details
Soil Type
Acidic, organic, moist, well-drained
Hardiness Zones
Zones 5 – 8
When to Fertilize
After bloom in spring through early summer; never in late fall
Fertilizer
Acid-forming (azalea/rhododendron) fertilizer
🌱 Growing Guide
Azaleas demand acid soil, a pH of about 4.5 to 6.0, that is moist, rich in organic matter, and above all well-drained, since their shallow roots rot in soggy ground and struggle in heavy clay; amend clay generously with compost and pine bark, or plant in a raised bed. Give them partial or dappled shade, such as the high shade of pines or morning sun with afternoon shade, because hot afternoon sun scorches the leaves and worsens lace bug attack. Plant shallow, with the top of the root ball slightly above grade, and never pile soil or mulch against the stem. Keep a two to three inch organic mulch (pine straw or bark) over the root zone to hold moisture and feed the soil, and water deeply in dry spells - they never want to fully dry out. Prune only right after bloom, since next year buds form by midsummer.
🌼 Have a different variety?Cultivars of the same species usually share the same basic care, and they differ mainly in flower color, height, and bloom form, not in how you grow them. So this guide still applies even if your exact variety isn't the one shown.
Planting Calendar
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Direct sow
Apr 15
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Projected first bloom
May 10
JJan
FFeb
MMar
AApr
MMay
JJun
JJul
AAug
SSep
OOct
NNov
DDec
✅ Plant alongside
Good neighbors that attract beneficial insects or deter pests
- Camellia: Shares the same acid soil and part shade and extends the bloom season, flowering before the azalea opens
- Hosta: Fills the shady ground around the azalea with bold foliage and enjoys the same moist, rich soil
- Ferns: Woodland companions that thrive in the same acid, humusy shade and set off the azalea flowers
🛡️ Pest & disease prevention
Proactive ways to stop trouble before it starts. Tap a name with an arrow for its full guide
The main azalea pest, stippling leaves grayish from sap feeding on the undersides - keep plants in their preferred part shade since full sun makes it far worse, check leaf undersides through the season, and treat early; healthy shaded plants resist it best
Fine stippling in hot dry weather - rinse foliage and keep plants from drought stress
A fungus that turns flowers to brown mush in wet springs - clean up fallen petals and avoid overhead watering while in bloom
Phytophthora kills plants in wet soil - the single best defense is sharp drainage and shallow planting; never let the roots sit in water
🌸 Blooms & cutting
Azaleas are grown for the spring show in the garden rather than for cutting, though a few flowering branches make a lovely short-lived display indoors - cut them in the cool morning as the buds open. The real maintenance is timing any pruning for right after bloom, since the plant sets next spring buds by midsummer and later cuts remove the flowers. Shearing is rarely needed; simply trim wayward shoots and remove any dead wood. Keep the root zone mulched and evenly moist year-round.
🥗 Nutrition & benefits
An ornamental woodland shrub grown for its spectacular spring flowers. The blooms offer nectar to early bees, butterflies, and hummingbirds, but every part of the plant is toxic, so its value is purely ornamental - do not let it be eaten.
⚠️ Toxicity & safety
All parts of azaleas and rhododendrons are seriously toxic - they contain grayanotoxins that can cause drooling, vomiting, weakness, an abnormal heartbeat, and even coma in dogs, cats, and horses, and they are poisonous to people too (even honey made from the flowers can be toxic). Plant where pets and children will not graze it, and never eat any part.
For educational and informational purposes only. HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.