Most red tip photinias that look sick are suffering from one fungal leaf disease, and it has driven many gardeners to give up on the shrub. The right fix depends on matching the symptom to its cause, and the shrub’s own habits, its tender red new leaves and its dense clipped shape, are behind several of its troubles.
Red And Purple Leaf Spots That Strip The Shrub
The usual culprit is Entomosporium leaf spot, a fungal infection of the leaves.1Bartlett Tree Experts. Photinia Leaf Spot: Identification, Biology & Management It starts as small, round red to purple spots on both young and older leaves. The spots grow and merge into larger maroon blotches, often with grey or tan centers. Badly spotted leaves yellow and fall, and an untreated shrub can lose a quarter to nearly three quarters of its leaves.2Journal of Environmental Horticulture. Entomosporium Leaf Spot Control on Red-tip Photinia in the Landscape A shrub hit year after year runs short of energy, thins out and can eventually die.
Early spots are tiny and easy to mistake for dust or insect specks, so look closely at the red new leaves on the lowest branches in the weeks after spring growth begins. Each spot enlarges over days to weeks, and new spots appearing on fresh leaves show the disease is active.
The fungus survives winter in last year’s fallen infected leaves.3Virginia Polytechnic Institute and State University Extension Division. Entomosporium Leaf Spot of Photinia In spring those leaves release spores, and splashing rain or sprinkler water carries them onto the plant.4Virginia Polytechnic Institute and State University Extension Division. Entomosporium Leaf Spot of Photinia Infection shows first on new growth of the lowest branches and works gradually upward.5Virginia Polytechnic Institute and State University Extension Division. Entomosporium Leaf Spot of Photinia Mature leaves resist leaf spot better.6Home & Garden Information Center. Photinia (Red Tip)
To confirm leaf spot rather than stress spotting, look at the fallen leaves under the shrub for the same maroon spots. Stress spotting shows up alongside poor soil, drought or exposure, and it doesn’t climb from the bottom. If you’re unsure, a local extension office can identify a bagged leaf sample.
Clipped hedges suffer worse than loose shrubs. Tight, frequently clipped hedges hold dense foliage that blocks airflow and keeps leaves wet.7University of Maryland Extension. Leaf Spot of Red Tip Photinia Each round of shearing also triggers a flush of new red leaves and thickens the outer layer so humidity gets trapped. Plants set close together pass splashed spores from one to the next.
The shrub also keeps feeding the fungus. It drops infected leaves, regrows red new growth, and gets infected again, draining stored energy each time.
How To Treat And Prevent Leaf Spot
Start with the habits that cut the fungus off. Prune red tips in winter while they are dormant, because pruning in the growing season pushes out new growth that the fungus easily attacks.8Home & Garden Information Center. Photinia (Red Tip) Rake up and remove fallen leaves, since they carry the fungus into next spring.9Virginia Polytechnic Institute and State University Extension Division. Entomosporium Leaf Spot of Photinia Water at the base rather than overhead, because splashing water spreads the spores.10Virginia Polytechnic Institute and State University Extension Division. Entomosporium Leaf Spot of Photinia Thin dense growth and space new plants so air can move through the shrub.11University of Maryland Extension. Leaf Spot of Red Tip Photinia
Rake the ground under the whole shrub, not just the visible pile on top. Bag the leaves for the trash rather than composting them, since a home compost pile may not stay hot enough to kill the fungus. Mulch laid over infected leaves doesn’t solve the problem, so rake first and then add fresh mulch.
Fungicides sprayed onto the leaves every two weeks gave strong control of leaf spot over several years.12Alabama Agricultural Experiment Station Bulletin. Entomosporium Leaf Spot Control on Red-Tip Photinia with Drench and Foliar Fungicides in the Landscape Shrubs sprayed with products such as Daconil Weather Stik, Immunox Multi-purpose Fungicide or RosePride Disease Control showed little if any spotting and no leaf loss.13Journal of Environmental Horticulture. Entomosporium Leaf Spot Control on Red-tip Photinia in the Landscape A soil drench of Bayer Advanced All-In-One Rose and Flower Care at label rates worked no better than doing nothing.14Alabama Agricultural Experiment Station Bulletin. Entomosporium Leaf Spot Control on Red-Tip Photinia with Drench and Foliar Fungicides in the Landscape At the drench rate, too little of its fungicide, tebuconazole, reached the leaves to protect them.15Journal of Environmental Horticulture. Entomosporium Leaf Spot Control on Red-tip Photinia in the Landscape For leaf spot, choose a product applied to the leaves rather than one poured on the soil.
A practical routine: start spraying as new spring leaves emerge, before spots spread upward. Repeat about every two weeks while new growth and wet weather continue. Cover both leaf surfaces and the lower branches thoroughly, and follow the label for rates and safety.
Spots already on leaves won’t disappear, so judge success by clean new growth. A badly thinned shrub may take a season or more to fill back in. If leaf spot returns every year despite your care, consider replacing it with a more resistant shrub.
White Powder On Leaves And Shoots
Powdery mildew begins as scattered cottony white to buff patches on the upper sides of leaves.16Pacific Northwest Pest Management Handbooks. Photinia-Powdery Mildew It thickens into grey-white powdery mats on both leaf surfaces, sometimes with tiny black specks.17Hortsense. Photinia: Powdery mildew Heavily covered leaves and shoots turn nearly white, twist, yellow and drop.18Pacific Northwest Pest Management Handbooks. Photinia-Powdery Mildew It is worst on soft new growth.19Hortsense. Photinia: Powdery mildew It spreads on wind-blown spores and thrives in shade, humidity, and warm days with cool nights.20Hortsense. Photinia: Powdery mildew
It’s easy to tell from leaf spot. Mildew is a white or grey surface coating you can partly rub off, while leaf spot marks are red to maroon and part of the leaf itself. Mildew favors shade and humid spells when leaves stay dry, while leaf spot follows splashing rain. Mildew often starts on the shadiest part, such as the north side or the area close to a wall or fence. A hedge can have both diseases at once, so treating one doesn’t rule out the other.
Grow photinia in full sun, and space and prune for good air movement.21Hortsense. Photinia: Powdery mildew Cut out and destroy badly infected leaves and twigs, and clean up fallen leaves.22Hortsense. Photinia: Powdery mildew A strong stream of water on both leaf surfaces can knock it back, but only when leaves can dry quickly.23Hortsense. Photinia: Powdery mildew Avoid overfertilizing, which pushes the soft growth mildew prefers.24Hortsense. Photinia: Powdery mildew
Yellow Leaves With Green Veins
Red tip photinia often shows iron deficiency: new leaves turn yellow while the veins stay green.25Urban Program Bexar County. Straight Talk About Iron Deficiency and Plants In alkaline, high-pH soils iron may be plentiful but is bound so tightly the roots can’t use it.26NMSU Cooperative Extension Service. Iron Chlorosis That’s why photinia is one of the plants most often brought to extension offices for this problem.27NMSU Cooperative Extension Service. Iron Chlorosis
Iron isn’t moved easily from old leaves to new ones, so the shortage appears first in fresh growth. On a red tip photinia, the new leaves that would normally be red may come in pale yellow or washed-out. In severe cases whole leaves turn yellow or cream and the edges can brown, so the green veins are most obvious early on.
Test soil pH before adding anything. A home kit or an extension soil test shows whether the soil is alkaline. If it is, chelated iron sprayed on the leaves greens them quickly, but the effect is temporary. Sulfur lowers pH slowly over seasons. Avoid planting near concrete foundations or lime-rich fill, which raise pH.
Wilting, Dieback And Rotting Roots
A water mold called Phytophthora can rot photinia roots.28Pacific Northwest Pest Management Handbooks. Photinia-Root Rot Poorly drained soil or flooding encourages the disease.29Pacific Northwest Pest Management Handbooks. Photinia-Root Rot Above ground you see yellowing between veins, slowed growth, limb dieback, wilting and eventually death.30Pacific Northwest Pest Management Handbooks. Photinia-Root Rot The fine feeding roots turn brittle and brown to reddish brown, or are missing entirely.31Pacific Northwest Pest Management Handbooks. Photinia-Root Rot Improve drainage or replant in a raised or well-drained spot, and remove shrubs that are already dying.
Root rot and drought look the same from above. Rotted roots can’t take up water, so the leaves wilt even though the soil is wet. Many gardeners respond by watering more, which makes the rot worse. Push a finger a few inches into the soil before watering to avoid that mistake.
To check the roots, dig gently at the edge of the root zone with a trowel. Healthy feeder roots are pale and flexible. Brown, brittle or absent roots with soggy soil point to rot, and wilting despite wet soil is a strong warning sign.
Water deeply but let the top few inches dry between waterings. Mulch holds moisture and reduces watering stress, but keep it off the trunk.32Bartlett Tree Research Laboratories Technical Report. Photinia Leaf Spot: Identification, Biology & Management Don’t plant replacements in the same soggy spot.
Insects That Attack Photinia
Aphids can be a particular problem on photinia, clustering on tender new shoots. As they feed they excrete honeydew, a sticky sweet liquid.33Home and Garden. Aphids On Photinia Black sooty mold grows on the honeydew, and ants gather to feed on it.34Home and Garden. Aphids On Photinia Wash aphids off with a strong water spray or use insecticidal soap.
Sooty mold lives on the honeydew rather than on the leaf, so scrubbing it off doesn’t fix the cause. Once the aphids are controlled, the honeydew stops and the black coating gradually weathers away. Heavy sooty mold can block light, but it rarely harms the plant directly. To keep aphids from returning, avoid heavy nitrogen feeding that produces the soft shoots they prefer. Ladybugs and other predators often control small outbreaks, and controlling ants helps, since ants protect aphids.
Adult root weevils chew notches in leaf edges at night, while their grubs feed on roots in the soil. To catch them, go out with a flashlight after dark, or shake branches over a pale sheet. C-shaped white grubs in the soil confirm larvae.
The grubs can be controlled with beneficial nematodes, tiny worms that hunt insects in moist soil.35Colorado State University Extension. Root Weevils The nematodes enter the grub and release bacteria that quickly kill it.36Journal of American Rhododendron Society. Practical Black Vine Weevil Management Apply them as a soil drench into moist soil above 52°F, which is late summer to early fall in places like western Washington. Read and follow the label directions carefully.
Pruning, Watering And Siting To Keep Photinia Healthy
Plant in full sun with space between shrubs, which discourages both mildew and leaf spot.37Hortsense. Photinia: Powdery mildew Mulching reduces water stress, suppresses weeds, and improves soil organic matter and beneficial soil life.38Bartlett Tree Research Laboratories Technical Report. Photinia Leaf Spot: Identification, Biology & Management A stressful site with poor soil, climate or exposure can itself cause spotting.39Bartlett Tree Experts. Photinia Leaf Spot: Identification, Biology & Management40Acta Horticulturae. Biodegradable Mulches for Weed Control in Container-Grown Photinia x fraseri ‘Red Robin’
Before you buy, look for a spot that gets sun most of the day and doesn’t hold standing water after rain. Leave enough room between plants for mature width so branches don’t crowd together. Avoid planting against walls that block airflow and keep leaves damp.
When pruning a hedge, shape it once in winter dormancy rather than shearing repeatedly in summer. Thin some interior branches so air reaches the center. Clean pruners between plants when disease is present, and bag and remove infected clippings rather than composting them.
Sometimes replacing beats rescuing. Shrubs leafless over most of their height for several seasons rarely recover well. A mixed hedge of different shrubs limits how far leaf spot spreads, and a less leaf-spot-prone shrub may beat years of spraying.