Pine pollen season in the Triangle: what to wash, what to leave, and when
The yellow film on everything in April is mostly harmless and mostly not what you’re allergic to, and it isn’t worth washing off yet. What actually needs doing, and when.
MyTriangleServices Editorial · · 5 min read
Some time in the second half of March, the Triangle turns yellow-green. It coats the cars on Hillsborough Street and draws tide lines on the sidewalk after rain. It even gets into a closed house through gaps you didn’t know you had.
Every year the same two mistakes follow it: people wash too early, and people wash with too much pressure. Both cost money. One of them costs a roof.
The yellow stuff is probably not what’s making you sneeze
The visible pollen is mostly pine, loblolly, which is the dominant pine across central North Carolina. Pine pollen grains are enormous as pollen goes, roughly 45 to 65 microns, which is exactly why you can see them piled on your windowsill.
It’s also why pine pollen is a comparatively minor allergen. Grains that big tend to settle out of the air and are too large to get far into your airways. The trees that reliably cause misery here, oak, maple, birch, juniper and cedar, release pollen you will never see on your car, and they’re releasing it at the same time. So the yellow film is best understood as a calendar rather than a cause: when the pines let go, the oaks are letting go too.
Practical consequence: washing the pollen off your house will not do a thing for your sinuses. It’s a cosmetic job. Which means it can wait for the right moment, and the right moment is not now.
Wash once, after it stops
The pine drop in the Triangle usually runs a few weeks from late March into April, with a heavy stretch somewhere in the middle. Washing your siding during that window buys you a clean house until the next dry, breezy afternoon, which is to say, until roughly Thursday.
Pine pollen is not corrosive. It isn’t eating your paint, your siding or your deck. It’s dust with good PR. There is no maintenance argument for getting it off in a hurry, so the move is to wait until the drop is genuinely finished, usually somewhere around the end of April, when the cars stop turning yellow overnight, and then do the job once.
Two things are worth doing during the drop, though, because they’re not cosmetic:
Rinse the outdoor AC unit. The condenser coil is a filter you never change, and a caked one makes the system work harder through the first hot weeks. Cut the power at the disconnect, then rinse the fins gently with a garden hose from the inside out. A pressure washer will fold the fins flat and you will have bought yourself a much larger problem.
Change your indoor filters. More often than the box says, in April.
The pressure washing part, where the real damage happens
When you do wash, the important decision is how hard.
Do not pressure wash asphalt shingles. The roofing industry’s own guidance (the Asphalt Roofing Manufacturers Association is the body that publishes it) is consistent on this: high pressure strips the mineral granules off the shingle, and those granules are the entire UV protection of the roof. You can take years off a roof in an afternoon, and you can usually void the manufacturer’s warranty while doing it. The damage doesn’t announce itself. You find out later, when the shingles are prematurely brittle.
If your roof has black streaks, that isn’t dirt and it isn’t pollen. It’s Gloeocapsa magma, an algae that eats the limestone filler in the shingle. The correct treatment is a soft wash: a cleaning solution applied at garden-hose pressure and gently rinsed off rather than blasted. Zinc or copper strips at the ridge slow it coming back, because the runoff is mildly toxic to the algae.
The same logic applies below the roofline:
| Surface | What it wants | What high pressure does |
|---|---|---|
| Asphalt shingles | Soft wash only | Strips granules, voids warranty |
| Vinyl siding | Low pressure, from above the seams | Drives water behind the siding |
| Painted wood | Low pressure | Peels paint, forces water into joints |
| Pine or cedar deck | Low pressure, wide fan | Gouges and furs the grain |
| Brick, concrete, pavers | Tolerates real pressure | Little risk, this is the one place to let rip |
Vinyl siding deserves a specific warning. Siding sheds water like shingles do, overlapping downward. Aim a pressure washer upward at it and you push water behind the panels, into the sheathing, where it has no route out. It won’t leak into your living room. It will just quietly stay there.
Gutters, which are the actual seasonal job
The pollen washes off eventually on its own. Pine needles don’t.
The Triangle’s pines drop needles as well as pollen, and needles are a worse gutter clog than leaves because they knit into a mat that water can’t get through and a leaf blower can’t lift. A blocked gutter in a spring thunderstorm sends water over the front edge and down against the foundation, which is how you get a wet crawlspace in a house with no plumbing problem at all.
If you do one outdoor job this season, clear the gutters. It’s the one with a failure mode that costs real money.
If you’d rather hand it off
Ask one question before you book: do you soft wash the roof, or pressure wash it? If the answer is anything other than an immediate, confident "soft wash", call someone else. It is the single question that separates the people who understand the surfaces from the people who own a machine.
Worth asking too whether they’ll be on the roof at all, and whether they carry liability insurance for it. We show insurance status on every profile where the company has given us a certificate to check.
In the directory, Heritage Exterior Cleaning is a Raleigh outfit that’s been trading since 1983; you can see the rest of the field on our list of pressure washing companies in Raleigh. Whoever you call, the question above is the same.
The short version
The visible pollen is pine, it’s mostly not your allergy, and it isn’t damaging anything.
Wait until the drop finishes, usually late April, then wash once.
Rinse the AC condenser gently now; change your filters.
Never pressure wash shingles. Soft wash, or leave it.
Clear the pine needles out of your gutters. That one matters.