Sweep during the bloom, clean after it
Jacarandas turn LA streets purple in late spring, and the flowers end up on driveways, sidewalks, patios and cars. The flowers are sticky, and once they get crushed under tires or shoes, or sit wet after watering, they leave purple, brown or gray stains on concrete.
Cleaning in the middle of the bloom is frustrating because the tree keeps dropping more. Most homeowners do better with frequent dry sweeping or blowing during the season, then one full cleaning once the tree is done.
Why the flowers stain
The blossoms carry a sticky residue, and the tree also drops sticky material that people often notice on cars parked underneath. When flowers are crushed, their pigment and that residue press into the pores of the concrete. Dirt sticks to the tacky spots, so stains darken over time. Leaves and seed pods add tannin stains on top.
Heat speeds it up. Crushed flowers on a sunny driveway can bake on quickly, which is why stains under the tree look worse by the end of the season.
During the bloom: habits that help
Sweep or use a leaf blower every day or two, while flowers are dry. Wet flowers smear and stick. Avoid driving or walking over fresh drifts when you can. Try to run sprinklers so they do not soak the driveway under the tree, since damp flowers stain faster.
If you notice a sticky spot, a quick rinse with water and a little dish soap while it is fresh often lifts it before it sets. Park cars out from under the tree if you have the option.
A leaf blower is often better than a broom on textured concrete, because it moves flowers without grinding them into the surface. Blow them into a pile on a dry patch and bag them for your green bin.
After the bloom: removing the stains
Once the drop is finished, sweep everything up and pre-treat the stained areas with a concrete-safe cleaner. A diluted oxygen-based cleaner is a good choice for organic stains like flowers and leaves. Let it dwell without drying, scrub the darkest spots, then rinse. A surface cleaner gives an even finish across the whole slab and avoids the stripes a wand can leave.
Many light purple stains also fade on their own with sun exposure over a few weeks. Sticky residue is different and usually needs a cleaner to break it down. Our tree sap post covers the stickier spots in more detail.
Do not forget the edges. Flowers pile up along walls, in expansion joints and at the bottom of the driveway apron, and those corners often hold the darkest stains. Give them extra cleaner and a bit more brushing.
Mistakes to avoid
Do not scrub dried flowers with a wire brush or blast them with a narrow tip. That can etch the concrete and leave marks that look worse than the stain. Be careful with strong bleach on colored or stamped concrete, since it can lighten the color unevenly. Test any cleaner in a hidden spot first.
Also, do not hose flowers and cleaner into the street. Los Angeles Municipal Code section 64.70.02 prohibits discharging untreated wash water from paved-surface washing into the storm drain system. Bag the flowers instead.
Timing a professional cleaning
If you plan to book a driveway or patio cleaning, schedule it after the tree finishes dropping, not at peak bloom. Otherwise you pay for a clean surface that gets covered again within days. Old stains from past seasons may only lighten, especially on light concrete that has gone years without cleaning.
If the tree hangs over the street and your neighbors get the same mess, it can make sense to coordinate. Cleaning several driveways right after the drop keeps the whole block looking fresh, and nobody tracks flowers onto a just-cleaned slab.
As of October 2026, driveway cleaning is $0.50 per square foot and patio cleaning is $0.65 per square foot, with a $195 minimum per visit. A 600 square foot driveway works out to $300. Booking both on the same visit earns a 5 percent bundle discount. Say Wash It confirms the flat price before work begins, and the instant quote on this page gives you a starting number.
Key points
Sweep during the bloom, clean after it
Jacarandas turn LA streets purple in late spring, and the flowers end up on driveways, sidewalks, patios and cars. The flowers are sticky, and once they get crushed under tires or shoes, or sit wet after watering, they leave purple, brown or gray stains on concrete.
After the bloom: removing the stains
Once the drop is finished, sweep everything up and pre-treat the stained areas with a concrete-safe cleaner. A diluted oxygen-based cleaner is a good choice for organic stains like flowers and leaves. Let it dwell without drying, scrub the darkest spots, then rinse. A surface cleaner gives an even finish across the whole slab and avoids the stripes a wand can leave.