Rhododendronspp.
Beloved for their delightfully bright and long - hold out flowers , azalea shrubs make a dazzling instruction in the spring garden . But there are also variety that flower in early summer and early fall .
So , with a scrap of provision , and a large enough garden , you’re able to bask those delicious blooms for up to eight months !
Some are beautifully fragrant , with a spicy or sweet , fruity aroma . And the leafage offer pretty decline colors as well .
Photo by Matt Suwak.
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shrub are available in a range of sizes and shapes with a uninfected , turn back profile that requires small maintenance .
And with over 10,000 file cultivars , there ’s a wide selection to choose from .
Photo by Matt Suwak.
In this guide , I ’ll cover everything you involve to know to cultivate azaleas in your garden .
Here ’s what ’s to come :
What You’ll Learn
What Are Azaleas?
Azaleas belong to to theRhododendrongenus , and they are members of the heath category ( Ericaceae ) .
Sometimes they ’re class into two decided subgenus , PentantheraandTsutsusi , other time they ’re two of the three main groups that make up theRhododendrongenus .
For the home gardener , what ’s important to remember is that they fall down into two types : deciduous and evergreen .
Most evergreen varieties are native to Japan , with a few species each from China , Korea , and Taiwan .
The evergreens grown in nursing home gardens are typically hybrids develop for improved calibre such as disease resistance , flowering time , and stale or heating tolerance .
The deciduous species are native to easterly Asia , easterly Europe , and North America .
Several aboriginal North American coinage ornament our gardens , such as Florida flame ( R. austrinum ) and pinkshell ( R. vaseyi ) . And other native species are used for breed purposes .
flora are often grouped according to their flower time , which may be early , midseason , or late .
The early bloomer typically flower from late winter through former spring . Midseason type flower in late fountain , and the late mathematical group flower from other summertime through fall .
Planting an assortment of dissimilar cultivar and species in your garden is an excellent way to enjoy their floral display for the full spring up season .
Check out our usher to azalea bloom of youth times to see more .
A Note of Caution:
Azaleas are highly toxic , and take in any part of the plant , or even azalea love , can bring forth spirit - jeopardise symptoms .
To be safe , keep your kids and pet away from these bush .
Cultivation and History
Ancient creative person and poets of both China and Japan have long lionise the beauty of azalea flowers .
In Japan , where most of the Asian varieties hail from , nurseryman at Buddhist monastery and royal palaces have cultivated and bred these ornamentals for over 500 age .
The first show acknowledgment date to the fifteenth century and Japanese classifications were first codified in 1692 in a text titledKinshu Makura , which translates to “ A Brocade Pillow . ”
Dutch bargainer first introduced Nipponese species into Holland in 1680 . later on , the British imported species from China . And in 1690 in Virginia , English botanist John Bannister recorded the first of several American coinage , the delightfulR. viscosum , or swampland azalea .
former American and British collector quickly jumped on the azalea bandwagon , sending plant and seed back to Europe for breeding purposes .
But it was n’t until 1825 in Ghent , Belgium , that the first hybrids from North American stock were successfully produce and recorded , with cultivars coming back to North America in the mid-1800s .
In their native habitat , mintage plants typically expand in Zones 5 to 9 . But in the mid-1950s , breeder at the University of Minnesota developed the first dusty hardy cultivar , significantly expanding their image of use in the garden .
Today , plant from the Northern Lights series are the intrepid that are commercially useable , with a selection of outstanding cultivars suitable for parky Zones 3 and 4 .
Azalea Plant Propagation
Youcangrow azaleas from semen . But because most of the usable parentage are loan-blend , seedling rarely regurgitate true to the parent plant life .
The only way to secure a clon of the parent plant is to propagate vegetatively , via stem cuttings or radical layering .
evergreen plant are the easy to distribute from cutting , while deciduous varieties typically give the best results when layer .
From Stem Cuttings
Ideally , you ’ll need to take semi - hardwood cuttings . This is the Ellen Price Wood that ’s still flexible , midway between tender new shoots and mature wood .
Layering
Layering is an leisurely process that involves encouraging origin evolution on a stem that ’s still tie to the parent plant .
The dependable meter to layer is in early spring before leave have emerged , but former fall works as well .
outpouring layered plantscanbe transplant into the garden in the fall of the same twelvemonth . But with either spring- or gloam - layer flora , waiting a year or two before transplanting is proficient .
This allows new plants to mature and gain size of it quickly in a familiar surroundings so that they proceed to thrive when moved to a new location .
To organ transplant , lop the parent stem close to the land .
Using a spade or trowel , loose the dirt around the contact bow , dig in just outside the dripline of the novel plant .
The dripline is an fanciful circle that extends from the uttermost branch tip all the way around the plant . Use this as a usher when digging up unseasoned shrubs – root increase is typically contained within the dripline .
Gently lift the root ball and transplanting to its raw location as described below .
Transplanting
Potted bush are best planted in natural spring or fall . For a showy video display , they require the right amount of Light Within , and soil with an acidic pH that ’s damp and well - draining .
Here are the planting dance step :
Plants can be spaced two to five animal foot apart , bet on their mature size .
Space two feet aside for plants that grow up to three feet at maturity , two to three feet aside for plants up to five feet , and three to five feet asunder for those greater than five foot .
show more about pass around azalea in our guidebook .
How to Grow Azalea Flowers
Providing the correct lighting is a key cistron to consider when institute azaleas .
Too much sun and they ’re going to shrivel up up and abide , but too fiddling brightness level and you ’ll have a unfolding shrub without any flush on it !
Dappled sunlight is the solution .
You ’ll need to position these shrubs in an area that receives either dawn light with afternoon ghost or in a place where they receive wide-ranging level of sunlight throughout the day . About six hours of Sunday in total , disperse across the sidereal day is idealistic .
A positioning with hot afternoon suncanbe endure , leave the soil is kept consistently moist . But be careful – the leaves of some species will fade from prolong , acute sunlight .
annul constitute close to south- or west - present walls – radiant hotness from wall surfaces can stimulate moisture loss and tension in hot spells .
Also , avert locating them directly under trees . Treesdoprovide filtered shade , but they also compete for water and nutrient , so place your bush at the edge of tree root zones .
Rich constitutional matter in the soil is necessary for plant health , and azalea prefer acid grunge with a pH between 4.5 and 6.0 .
If you ’re incertain of your soil ’s pH , test the soilbefore planting and amend as need with ammonium ion sulphate or garden sulfur , per package directions .
skilful drainage is a must - have for these plants to flourish . Azaleas can not abide wet pes , so it ’s life-sustaining to obviate site that are prostrate to standing water .
Soil that ’s Lucius DuBignon Clay based or otherwise heavy and dense retains too much urine , and flaxen grease drain too speedily .
If your soil is weighed down , add one to two shovelfuls of landscape painting gumption or pea gravel to better drainage .
Conversely , if your filth is flaxen , meld in one to two shovelfuls of peat moss . This will help hold wet , and members of the Ericaceae family love the acidic nature of peat .
If your soil precondition are less than ideal , considerbuilding a bring up bedor imbed them in container or else .
you’re able to get the lowdown onhow to grow azalea in containers in this usher .
Whatever the soil texture , before implant it ’s good to generously fuse compost with the subsist topsoil , adding it at a ratio of one part compost to one part topsoil .
Azaleas require aboutone column inch of piss per calendar week , so if your rain stratum are on the low end of the scale , plants will needsupplemental irrigation .
When tearing , fend off overhead irrigation if potential – it encourage foliar disease like leaf gall and petal blight .
If overhead irrigation is unavoidable , H2O in the early morning and allow the Lord’s Day to dry the smashed leafage .
A cloudburst hosepipe is an ideal option for water most plant in the garden . Set one up and work on the hosepipe bib or impart a timer for all hands - free watering .
50 - foot Soaker Hose
dipsomaniac hoses areavailable at Home Depot .
Fertilizing is easy as well . A layer of well - rotted compost apply annually as a mulch will add enough constitutive material to keep plant well fed and substance .
If supplementary feeding are needed to improve efflorescence or vigour , apply a plant food designed for window pane - bang plants in the spring .
Down To Earth Acid Mix
Down to Earth make a 4 - 3 - 6 Acid Mix fertiliser that is idealistic for azaleas and isavailable at Arbico Organics .
Mulching is beneficial as it helps the grime to retain wet , forbid weeds , and adds nutrients as it breaks down .
Acidic pine needles are one of the in force types of mulch to use with these flora . you’re able to source them topically from your own yard or a local parkland , and you’re able to even buy them online .
Long Needle Pine Straw Mulch
Pine wheat mulch isavailable in 300 - square - foundation box from Home Depot .
yellow leaves , but no foretoken or symptom of gadfly problems , could intend your plants have an iron deficiency called chlorosis which can be cover with a topical software of iron .
Biomin Iron
Five - gallon container of Biomin Iron areavailable at Arbico Organics .
Calcium inadequacy are another offspring with these plants , indicate by inwards curling leaves and leaf backsheesh burn mark .
This can be treated with an software of gypsum or even crush oyster shells , if you ’ve got those rest around in your garden shed .
Growing Tips
When provided with the right growing shape , azaleas are highly rewarding ornamentals that are promiscuous to cultivate and require little sustenance .
Check the following crown to get the most from these lovely shrubs :
Pruning and Maintenance
All pruning should be performed in the springtime immediately after the shrub flower .
Azaleas , likefuchsias , start to form next year ’s flower bud before long after they finish blooming , so pruning in this narrow window is ideal .
If you rationalize too latterly , you put on the line cutting off next year ’s buds , which results in few heyday .
A measuring stick of the appeal of these plants is their informal growth habit , so seek to prune them into a boxlike shape will be ineffective .
heavily pruning should also be avoided because it results in atypical patches of flowers . After they ’ve been pruned , new growth flushes ahead to rejuvenate the industrial plant – but you ’ll need to wait two or three years before you ’ll see bloom again .
Take a step back and imagine the form you ’re looking for before pruning .
If you ’re reducing the overall sizing of the shrub , check to determine what arm locomote where and thin as few times as possible . Remember , you may take it off but you ca n’t put it back on .
determine more about how to snip azaleas in our scout . ( fare soon ! )
Deadheadingisn’t required , but you’re able to withdraw spend blooms to tidy up appearances if desired .
And winter care is straight . Reduce watering at the end of the get season and add a thick , three- to five - inchlayer of mulchof shredded leaves , pine needle , or shuck to protect beginning against freezing and thaw cycles .
If unusually insensate weather condition is forecast , plants can be covered with a porous material such as burlap or an old bottom sail to protect against freezing temperatures .
expend landscape pin to anchor cover to the ground until seasonal temperatures refund .
For more details , check out our guide to azalea winter care . ( coming soon ! )
Azalea Cultivars to Select
As bring up , azaleas are generally divided into two types – deciduous or evergreen . And aside from temperature circumstance , they all bask the same introductory growing shape .
When select , remember that evergreen types are fond of strong climates and wo n’t hold up in freezing temperatures . Look to the deciduous coinage and cultivars for cold - audacious flora .
Now , here ’s a sampling of some democratic varieties .
Bloom-A-Thon
breed for a longer flowering time of year , ‘ blooming - A - Thon ’ is a vigorous reblooming serial publication , providing up to five month of bright , spicy pink bloom .
These bush first give a vigorous flush of flowers in mid - spring that lasts four to six weeks then rebloom with a 2d wave of bloom that last 12 to 16 week from early summer through nightfall .
Plants have a compact growth habit . ripe heights are between two and four feet , with a spread head of one to four feet . This makes them idealistic for planting in assorted beds , borders , container , and rock garden .
‘ efflorescence - A - Thon ’
An evergreen shrub , these flora have been engender to cover more hours of full sunlight better than many other type .
For reblooming shrubs , a light clipping is recommended after the first bloom to advance more summer and fall heyday . Hardy in Zones 7 to 9 .
Container plants areavailable at Nature Hills Nursery .
Northern Highlights
Bred for the dusty , ‘ Northern Highlights ’ come up from the breeding program of the University of Minnesota ’s Landscape Arboretum .
racy shrubs feature large , creamy blanched blossom that originate a sassy yellow splattering on the upper flower petal .
The blossom are sweetly fragrant and bloom from early to mid - spring . And the mildew - tolerant foliage give a pretty fall evidence in shades of burgundy and purple .
‘ northerly Highlights ’
Terrific for mixed beds , borders , and fundament planting , these bush have a compendious visibility with a acme and spread of four to five feet . Hardy in geographical zone 4 to 9 .
Plants in Imperial gallon - size containers areavailable at Home Depot .
Red Mollis
The gorgeous Mollis series of hybrids are roll in the hay for their large , lush blossom clusters in juicy , tropic coloring material .
First bred in the early 1800s in Belgium , these attractive shrubs are still extremely popular today .
Red Mollis sport large blooms of ruffled , recurve huntsman’s horn in a vivacious fire red , flowering in late spring to early summer . And there ’s more color in drop , when the leave-taking give an attractive display in shade of orange , red , and yellow .
Outstanding for foundation planting , flowering hedges , motley perennial bed , and shrubscapes , plants hold a goodish visibility with a height of four to six metrical unit and a spread of three to four feet . Hardy in Zones 5 to 8 .
need More selection ?
Be trusted to read our supplemental guide:21 of the Best Azaleas for Your Garden and Yard .
Managing Pests and Disease
If your azalea is grow in the good piazza , you wo n’t need to worry much about pests and disease problems .
Insects like caterpillars andlace bugscan be handwriting - find fault or treat with an insecticidal soap .
Underground , nematodes can aggress the root . Unfortunately , there ’s no discourse for this . channelize off problems before they start with a sound and disease - tolerant cultivar plant in the correct location .
More serious issues may be due to barque ordered series , whiteflies , andleaf miners .
Bark plate blackens branches and appear as small , ashy or blanched cottony bit and a sticky jet-black message on the Ellen Price Wood . Your good bet is to bump off the septic branch and outgrowth , and then cast away of them .
whitefly will do yellow , wilt , and become flat leaves . Use neem rock oil to fend them off .
The azalea leaf miner ( Caloptilia azaleella ) is a much more serious pest , and dealing with an infestation may require removal of septic plants .
Leaf miner are moth larvae deposited on the underside of leafage . They tunnel inside the foliage and as they mature and feed , small brown blisters look then leaves brown and curl at the tips and margins .
As for disease , powdery mildew , caused byErysipe azaleae , and petal blight ( Ovulinia azaleae ) are common fungal problem that can generally be control with a antifungal .
Powdery mildew appear as a fuzzy white or white-haired dot on farewell and stems . watch to cover powdery mould in this guide .
Petal blight first appear as small , waterlogged spots on petals that quickly merge , induce peak to change state worthless and decompose .
More serious disease issues include branchlet blight and rust fungus . Twig plague , a fungal disease caused byBriosia azaleae , results in the bud and twig tips turn browned and dying .
Rust can be because of one or more species of fungus in thePucciniastrumgenus . It appears as pale green to yellow dots that form splodge of yellow to orange spores .
remotion and electric pig of infected farewell and branches is the only safe solution for these infections .
Best Uses for Azalea Shrubs
With brilliant flash of color in a sea of unripe foliage and delicious structure , azaleas make a perfect argument piece .
They act in interracial bed and borders and are grand planted as a flowering hedging . And some of the smaller ones are a standout in rock garden .
Or try some on the terrace in great container or pots .
For a tolerant sweep of colour , a dozen plants placed together give maximum effect and can be attractively offset with inflorescence perennials likeblack - eyed Susansor a sweep ofornamental grasses .
Quick Reference Growing Guide
For Beautiful Spring Color
When provided with the right location and develop condition , azaleas are a instinctive , go - to choice for beautiful spring color .
With an unrestrained growth habit , they add architectural interest all year and look striking when pair with other plants that make love the same circumstance , likeastilbe , lily of the vale , ortrillium .
And for more info about growingflowering shrubs , check out these guides next :
photograph by Matt Suwak © Ask the Experts , LLC . ALL right RESERVED.See our TOSfor more details . Originally published January 31 , 2019 . Last updated February 19th , 2023 . revise and expanded from an original clause by Matt Suwak . merchandise photos via Arbico Organics , Home Depot , and Nature Hills Nursery . Uncredited photos : Shutterstock .
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Lorna Kring
