How do we stop powdery mildew on our HOA's crape myrtles?

By OurHOA · General information · Revised October 31, 2026

How an HOA board stops powdery mildew on common area crape myrtles: resistant cultivars, sun and air flow, sucker removal, fungicide timing and a replanting plan.

Part of the HOA board handbook: vendors, projects and upkeep.

The short answer

Powdery mildew on crape myrtles is mostly a cultivar and site problem, so the cheapest fixes are cultural. Have the crew strip basal suckers, thin crowded canopies, keep sprinklers off the leaves and clear fallen leaves in fall. When a tree has to be replaced, plant a resistant cultivar in full sun. Spray fungicide only on small, high-visibility trees with a history of bad mildew, starting at the first sign in spring. Clemson Extension says control on large trees is usually not feasible because the spray can't cover the foliage well. The disease is caused by the fungus Erysiphe lagerstroemiae. UF/IFAS calls crape myrtle one of the most common landscape plants in north and central Florida, and the Texas Plant Disease Handbook calls powdery mildew very common on it. UF/IFAS puts the plant's range at USDA hardiness zones 7 to 9, so Colorado boards will rarely manage it. Treatment rules and who maintains trees on owner lots vary by state and by your governing documents. This guide is general education, not legal advice.

Confirm it is mildew

Texas A&M AgriLife's plant disease lab describes a grayish-white, powdery growth on leaves, shoots, buds and flowers, mostly on new growth. Badly infected leaves curl and twist, shoots can shrivel, buds abort and drop, and severe cases bring early leaf drop. Clemson and NC State Extension add that heavily infected flowers may fail to open. Late in the season the fungus forms tiny dark bodies about the size of a poppy seed. They survive winter on leaves and debris and release spores the next spring. Two look-alikes to rule out. Black coating on leaves and bark is sooty mold, which grows on honeydew from crapemyrtle aphids or bark scale, not mildew. White felt-like specks on the bark itself, often with black bark, point to crape myrtle bark scale. Our guide on treating crape myrtle bark scale covers that pest. If you aren't sure, a county Extension office can identify a bagged sample.

When it strikes and when it rests

Mildew is a spring and fall disease. Texas A&M says warm days and cool nights of about 60 to 80 F favor it, that spores spread on the wind and can infect within three to five days of landing, and that they don't need water on the leaf, only humid air. Growth may stop when leaf temperatures pass 90 F. Clemson puts it as humid nights and dry, mild days. UF/IFAS says it is most active in the cool, dry periods of spring and fall and most severe in shade. The University of Arkansas adds that symptoms can appear within a week of infection. That pattern tells the board when to act. Scout new growth from leaf-out through early summer, and again when nights cool in September and October. Texas A&M notes that fungicides are usually not needed in the hottest part of the year, when the fungus is inactive and some products can injure the plant. A summer bid for mildew spraying is a sign the vendor isn't reading the calendar.

Fix the site before you spray

Extension sources agree that prevention beats treatment. Write these into the landscape contract: - Remove suckers at the base as they appear. Clemson and NC State both say suckers are susceptible and pass the fungus up into the tree. In practice that is a monthly line item from April through September. - Thin the canopy during the winter pruning so leaves dry quickly. NC State recommends it, and our guide on pruning HOA crape myrtles without topping them covers the cuts. Topping forces a flush of new shoots, and new growth is where mildew hits hardest. - Keep irrigation off the foliage. Arkansas says reducing leaf wetness cuts infection. Adjust spray heads that wet the canopy. - Go easy on nitrogen. Texas A&M lists excess fertilization as a contributing factor. - Rake and remove fallen leaves in fall or winter. Arkansas and Texas A&M both say infected leaves carry the disease into spring. - Cut out heavily infected shoots when only part of a tree is affected. Shade is the hardest fix. Crape myrtles planted under oaks, against a north wall or in a crowded entry bed will keep getting mildew, and replacing them with a plant suited to shade may be the honest answer.

Plant resistant cultivars when you replace trees

Every crape myrtle the association replaces is a chance to end the problem for good. Clemson's fact sheet, revised in 2026, says the Lagerstroemia indica x fauriei hybrids from the U.S. National Arboretum are resistant. It lists 'Apalachee', 'Caddo', 'Fantasy', 'Hopi', 'Lipan', 'Miami', 'Osage', 'Pecos', 'Sioux', 'Tonto', 'Tuscarora', 'Tuskegee' and 'Wichita' among those with very good resistance, and calls 'Apalachee' and 'Fantasy' totally resistant. Texas A&M names 'Tonto', 'Muskogee', 'Acoma', 'Sioux' and 'Tuskegee'. Clemson and NC State both say to avoid 'Carolina Beauty', 'Gray's Red', 'Orbin's Adkins', 'Wonderful White', 'Raspberry Sundae' and 'Potomac'. Three cautions. Clemson notes that resistance can vary by location. UF/IFAS reports that mildew-resistant crape myrtles appear highly susceptible to crapemyrtle aphids, so expect some aphids and sooty mold in summer. And pick the cultivar by mature size as well as resistance, so the tree fits its spot without ever being topped. Put the cultivar name on the planting plan, ask the installer to leave the nursery tags on until a board member checks them, and reject substitutions that aren't on your approved list.

When fungicide is worth paying for

Spray only where the payoff is clear: a few small trees at the entrance, the pool or the clubhouse with mildew every year. The University of Arkansas says woody plants with persistent mildew may need regular systemic fungicide, and that applications should begin in spring at the first evidence of disease. Texas A&M's handbook also says to start at first appearance. Active ingredients named by Extension include myclobutanil, propiconazole, triforine and triadimefon (Arkansas and NC State), thiophanate-methyl and copper products (Clemson), elemental sulfur (Arkansas), and neem oil extract and potassium bicarbonate (Texas A&M). Clemson says multiple applications may be needed. Follow the label for rate, interval and plant safety. Compare the cost over five years. A season of repeat sprays on a few entry trees recurs every year, while replacing a susceptible tree with a resistant cultivar is a one-time cost. For large, established trees that would be expensive to replace, accept some mildew in spring and fall and lean on the cultural steps above.

Who may apply it

Fungicide is a pesticide, and paid application is licensed work. - Texas. Tex. Occ. Code 1951.003(a)(1)(B) treats controlling pests or diseases of trees, shrubs or other plantings in a park or next to a residence, for pay, as structural pest control. Section 1951.301(b) requires a structural pest control business license. Ask for the Texas Department of Agriculture license number. - Florida. The limited landscape maintenance certification in Fla. Stat. 482.156(1) allows integrated pest management on ornamental plants only with products that carry no signal word or the word "caution," applied with handheld equipment or backpack sprayers. A product labeled "warning" or a power sprayer needs a full pest control license. Collect the license number and a certificate of insurance before the first application.

Sample calendar, motion and owner notice

A sample year. January and February: winter pruning that thins without topping, and removal of leaf litter under the trees. March: approve the year's scope, including monthly sucker removal and any spray program for the few trees that need it. April to June: scout new growth every two weeks, with the first fungicide application at first sign on approved trees only. July and August: no mildew spraying. September and October: scout again as nights cool. November and December: list trees with chronic mildew and put resistant replacements in next year's budget. Motion: "Move that the association amend the landscape contract with [contractor] to add monthly crape myrtle sucker removal from April through September, and approve spring fungicide treatment of the crape myrtles at [locations] at first sign of powdery mildew, at a cost not to exceed $[amount] for [year], with the contractor's license number and certificate of insurance on file before the first application." Owner notice: "The white coating on some neighborhood crape myrtles this spring is powdery mildew, a common fungus that curls new leaves and can keep flower buds from opening. The association is removing suckers, thinning canopies and replacing the worst-affected common area trees with resistant varieties. If you are planting a crape myrtle on your lot, ask the nursery for a mildew-resistant cultivar." The mistakes that keep trees white: replanting the same susceptible cultivar, topping trees every winter, letting suckers grow all summer, spraying big trees that can't be covered, spraying in July, and wetting the canopy with sprinklers every night.

Sources

These guides are general education for HOA boards and residents, not legal, tax, or financial advice. Rules vary by state and by your community's governing documents - check with a professional for your situation.

More on living with an hoa

Or browse all living with an hoa guides.