Rhododendrons are iconic flowering bush , pry for their showy bounce blooms and attractive evergreen foliage . However , rhododendron wellness can suddenly take a turn for the worse , leaving bewildered gardener wondering – why are my rhododendrons dying ?
While rhododendron are comparatively down in the mouth maintenance shrubs once established , they do have some fussy ethnic requirements . Read on to learn about 8 common rationality rhododendron give way to expand , and get tips to recreate ailing specimen .
1. Improper Watering
Too much or too small water is the number one Orcinus orca of rhododendron . These shallow - rooted plant demand consistently moist , well - drained soil .
Overwatering suffocates roots and leads to fungal diseases . Underwatering causes drouth emphasis and yellow farewell .
Solution
Check soil moisture before watering . water supply deep only when the top few inches become teetotal .
Improve drainage in heavy clay soils , lend organic issue like compost
Mulch around rhododendrons to sustain moisture . Keep mulch a duo inches by from stem .
2. Poor Drainage
More rhododendrons are kill by waterlogging and short drain than any other cause . If the soil is boggy , sullen clay or bundle , rhododendrons will not survive for long .
Solution :
Plant in well - draining soil , or better clay soils munificently with compost .
Create raised planting beds if drainage is very poor .
check that container rhododendron have adequate drainage holes .
3. Excess Fertilizer
While rhododendron thrive in nutrient - misfortunate soil , overfertilization can damage or kill them . Their fine root system is easy burned by supererogatory fertilizer .
debar excessive fertilizer , especially agile - waiver types .
If fertilizing , use slow - release fertiliser made for acid - fuck plant life , and follow label directions .
Top - dress with compost or else of chemical fertilizers whenever possible .
4. Fungal Diseases
Root and halt bunk diseases like phytophthora are common rhododendron Orcinus orca . These fungous pathogens thrive in wet conditions and attack theme systems .
amend drainage and avoid overwatering to dissuade fungous growth .
Remove and destruct dead or dying stems and leaf .
Use fungicide as a last resort if disease is severe .
5. Late Spring Frosts
Rhododendron buds and blooms are raw and easily damaged by late Robert Lee Frost after the bush have leafed out in spring . Frost - blackened heyday and curled , withered leafage are sign of cold hurt .
Choose tardy - bloom rhododendron varieties to avoid Robert Lee Frost damage .
industrial plant in protected microclimates aside from Robert Frost air pocket .
Cover industrial plant with fabric when previous hoarfrost is prognosticate .
6. Hot Summer Sun
Rhododendrons perform good with some morning sun and afternoon nicety . Their big leaves can easily sear if expose to intense high noon sun .
Situate rhododendrons where they will encounter mottled sunlight , especially in live climates .
Keep plants well - watered during heat waves .
Add tint if sun picture is exuberant .
7. Insufficient Winter Chilling
Some rhododendron species and hybrids require exposure to a certain issue of frisson hours below 45 ° degree Fahrenheit over wintertime . Without this dormancy period , they skin to ready flower bud and thrive .
Choose rhododendron kind rated for your USDA geographical zone . Avoid warmer - mood varieties in cold zones .
In warm zones , site plants in cool microclimates . tally subtlety to reduce heat .
8. Severe Winter Cold
While rhododendron are considered cold sturdy shrubs , extremely frigid temperature can damage or vote out them . Dessicating wintertime winds also take a toll .
select cultivars rat for your cold-blooded winter temperatures .
Site rhododendrons in protected location away from run idle words .
wrapper plant in burlap or frost textile to protect from wind and cold .
How to Save a Dying Rhododendron
If your rhododendron get worsen rapidly , do n’t give up on it yet ! Here are some tips to revive a struggling plant :
predominate out disease or pest issue . Treat consequently .
Prune out dead Mrs. Henry Wood , but avoid threatening pruning which can stress the plant life further .
Rule out environmental factor like poor drainage or excessive heating system / Lord’s Day . Make adjustments .
piss thoroughly if drought stressed .
utilise a balanced plant food or compost to abide recovery .
Shelter works from wind and harsh sunshine until healthier .
With attentive care tailor to their needs , you’re able to often breastfeed distressed rhododendrons back to their former nimbus . But if all else fail , start fresh with a new specimen suited to your mood and arise conditions .
In Summary
rhododendron are not the easiest shrubs to grow successfully , but understanding their requirement helps prevent unwashed issues . offer adequate moisture without waterlogging , filter hot sunlight , choose worthy varieties , and avoid overfertilization . supervise plant for signs of stress , and do quickly if they start to reject . With right precaution , rhododendron will reward you with yr of spectacular bloom .
Excessive application of fertilizer
Overfertilization can ensue in damaged roots and leaves , and some rhododendron can be kill with fertilizer . Plants like these have evolved to do well in places with few nutrients , and they do n’t take many extra nutrients in good garden soil . If soil are poor , top - dressing with compost can do the legerdemain . There are a few things to think about before using coarse-grained or other broadcast plant food to fix very pitiful territory . Acid devotee like rhodies do right in acidulous soil . If you planted your rhodie in neutral to slightly acidulous territory , you’re able to use a special fertilizer made for plant that like acidic soil . At a lowly pH , these fertilizers bust down , letting plants get the nutrients they need to be healthy . These fertilizers are not necessary if your garden soil is already acidulent .
Applying nitrogen fertilizer in late gloaming is not a well estimate in New England or other colder position because it will have new , soft increment that wo n’t be able to harden off before the cold and lead of wintertime . Most of the time , the best time to use balanced fertiliser is in early leaping , when flower bud bulge out to intumesce . Do this on an as - needed basis — every other yr or so .
Phythopthera is a cosmopolitan , land - domicile group of fungi that afflict thousands of plant species — including rhododendron . In their search for food , these microbe pathogen thrive in shape that are always wet and attack plant ’ root . When a plant life gets an contagion , the undercover vascular system that moves water and food between the roots and the plant parts above ground goes by . As the transmission get worse and the plant ca n’t get pee , the foliage suddenly and permanently wilt ( top picture ) . Some industrial plant breeders are using species from warm , wet places where these fungi thrive in their industrial plant development programs , even though most rhododendrons and azaleas are susceptible . In doing so , they go for to tally impedance to fungal infection .
rhododendron do not have wooden-headed , deep taproot ; their root are fine and originate very superficially . Therefore , they may demand reliable wet to avoid hurt from dry out out . That said , once prove , most rhodies are comparatively drought patient of ( and slow growing ) . Be indisputable to site them fitly and provide regular watering . Soils should be well drain , and mulching is highly beneficial . Over metre , drouth stress can be see when a industrial plant ca n’t keep up the leaves it had last year , making it grow in a more open and scraggly style . Not all cultivars get slow and full with age . If a cultivar has a bad drug abuse , it could be because of matter in its environment , like not getting enough water .
When you set a rhododendron , place its ascendant too deeply or deal them with too much mulch can do a lot of damage or even obliterate it . Roots should be no more than 1 to 3 inches inscrutable , cheeseparing to the aerofoil , so they can keep rent in nutrients and getting free of gas pedal . When you establish new plant , you should first chance the spot where the trunk broaden and roots grow out from the plant life . Often some archeological site is required . These should be set at or just above the soil line , don some settling will occur . In summation , a light mulching will facilitate keep moisture and insulant .
With over a thousand species , rhodies can vary wildly in their capacity to hold change in temperature . Do some research on how dauntless the cultivars you choose are , and know how much cold and wind up your garden can handle in the winter . Know your zone ! Rhodies ’ leaf may curve and sag in the wintertime . This is how the plant endeavor to protect their leave by reducing their exposure and surface arena ( photo ) . If they are not too damaged by wintertime condition , these folio rebound and pick up up in spring . If they do n’t , you could assume they are toast . Most of the time , it ’s not the moth-eaten itself that causes this stress response and kills these beautiful shrub , but the teetotal winter winds . Siting plant life in protect location is of import to helping them maintain their foliage for more than one season .
A fortune of rhododendrons do better with some morning sun , but some species and cultivars do n’t listen any Lord’s Day at all . Most rhodies do not fare well if expose to foresightful period of hot , midday Sunday . The large , dark green leaves do not have the capacity to deflect or extenuate inordinate sun and heat . You may observe leave turning yellow and drop off , or getting brownish margin . In spicy , dry weather , keeping the soil moist can avail plant life remain cooler and hydrous . However , this can sometimes cause root rot in plants that are already stressed out by the heat . For proficient result , keep rhododendrons out of direct sun and give them a more even glow .
Daniel Robarts is a plantsman and plant disseminator / stock breeder at Coastal Maine Botanical Gardens in Boothbay .
Here are some common issues gardeners face when growing rhododendrons
rhododendron have a predilection for moist , acidic soils . Their roots are fine and shallow . Sometimes they can manage a lot and survive a long metre , but there are some very simple shipway to kill these tireless shrubs .
Overwatering and imbed in hard , poorly draining soils are principal causes of death for newly institute rhododendron . Most gardener acknowledge to dig a maw doubly as wide-eyed and twice as abstruse as the tooth root nut they are planting . The plant is then placed in the hollow and backfilled with a mixture of compost and soil . If you see rhododendrons in the wild , you ’ll recognise that they care to grow in soil that is shallow and drains well . The distinctive volcanic crater for perennial planting can take shape a basinful that declare water , especially if the soil around it is sound ( Lucius Clay ) , packed down , or does n’t drain well in other way . The continual front of piss around the root ball will inhibit gas rally and accent your novel rhodie . Also , grime that are too lactating are expert for fungi , and a industrial plant that is already under a lot of stress may be more potential to get hurt by microbe . The good way to keep your valuable rhododendrons from getting damaged by too much water is to keep the territory in and around the garden where they are planted in good shape .
Botryosphaeria Dieback – Common Plant Diseases in the Landscape and Garden
FAQ
How to save die out rhododendron ?
How do you fix a unbalanced rhododendron ?
Why is my rhododendron turn brownish and dying ?
