How Cedar Pollen Season Affects Your Home’s Exterior in Austin (And Why Spring Pressure Washing Matters)

Every Austin homeowner knows cedar season — that yellow-green haze that drifts in around Christmas, peaks in mid-January, and turns the city’s tissues, eyes, and sinuses into casualties. What most people don’t realize is that the same pollen wreaking havoc on your sinuses is doing a quieter, slower kind of damage to your home’s exterior.

By the time spring arrives, your siding, driveway, roof, and patio have been coated in a fine biological film for two to three months straight. And cedar pollen, on its own, isn’t really the problem. It’s what cedar pollen does when it sits on a damp surface for weeks that turns it into a maintenance issue.

What cedar pollen actually is — and why Austin gets so much of it

The “cedar” in cedar fever is technically Mountain Cedar (Juniperus ashei), an evergreen native to the Edwards Plateau and Texas Hill Country. Despite the name, it’s a juniper — and Central Texas sits in the densest concentration of Juniperus ashei stands in North America.

Each winter, in response to cold fronts, male cedar trees release massive plumes of pollen — visible as yellow-green clouds drifting from individual trees on calm mornings. A single male juniper can release billions of pollen grains over the season. Multiply that by the millions of trees in the Hill Country and you get one of the most extreme pollen events anywhere in the world.

The pollen grains themselves are tiny — about 20–25 microns — small enough to slip through window screens, ride air currents for miles, and settle invisibly into every porous surface around your home. That’s why even homes with no junipers on the property still end up coated.

Why pollen alone isn’t the problem — it’s pollen plus moisture

Dry pollen brushes off. The issue is what happens when pollen sits on a damp surface during a typical Austin winter, where overnight dew, occasional rain, and humid mornings keep most exterior surfaces wet for hours every day.

Three things happen:

• The pollen rehydrates and adheres. Cedar pollen contains protein compounds that become tacky when wet, then dry to a film that bonds with the surface.
• It feeds biological growth. Pollen is organic matter. On siding, roofs, and deck boards, it becomes a food source for the algae, mold, and mildew already lurking in Austin’s humidity.
• It traps dirt. The sticky film captures airborne dust, limestone particles, and exhaust soot, building up the visible yellow-green-to-gray haze that takes hold by February.

Multiply that across a 12-week pollen season and your home doesn’t just look dirty by spring — it’s accumulated three months of bonded biological debris.

What cedar pollen does to specific surfaces

The damage profile varies depending on what your home’s exterior is made of. Here’s what we see most often when Austin homeowners book their first wash of the year:

For a deeper dive on each surface type and which method to use, see our Complete Guide to Pressure Washing in Austin.

Why north and east-facing surfaces always look worst

If you’ve noticed that the north side of your house always seems dingier than the south, you’re not imagining it — and cedar season makes it worse.

North and east-facing walls get the least direct sunlight, which means surfaces stay wet longer after dew, fog, or rain. That extended moisture window gives pollen the time it needs to bond, and gives algae the food and conditions to colonize. By April, the contrast between your sunny south wall and your shaded north wall is usually dramatic.

Same effect explains why black streaks on your roof almost always start on the north slope first.

When to wash: timing your cedar season cleanup

The single most common mistake we see Austin homeowners make is washing too early — in January or February — only to have the next big pollen drop recoat everything within days.

Wait until cedar counts have dropped consistently for a week or more — typically late March in Austin — then book the wash. You’ll get the longest possible “clean” window before next December.

Here’s the realistic calendar:

• December – February: Active pollen accumulation. Don’t full-wash unless you’re listing the home or hosting a major event. Spot rinses are fine.
• Early–mid March: Cedar counts drop but oak pollen is now ramping up. If you can wait two more weeks, do.
• Late March – early May: The sweet spot. Cedar is gone, oak is fading, temperatures are mild enough to avoid flash-drying soft wash solutions. This is when most of our spring bookings happen.
• May – August: Still effective, but heat shortens dwell time and increases the workload on the crew. Schedule earlier in the day.
• September – November: Second-best window — clean before holidays and before December cedar starts the cycle over.

Can you DIY the cedar cleanup?

For some surfaces, yes. For others, you’ll spend more on rental equipment than a professional would charge — and risk damaging the surface in the process.

The benefits of a proper post-cedar wash

Beyond making your home look like itself again, a well-timed spring wash delivers four concrete benefits that homeowners often underestimate:

• Halts biological growth. Killing the pollen-fed mildew and algae now prevents the much larger problem of established colonies by midsummer.
• Resets your maintenance clock. A clean exterior in April typically stays presentable until the fall — meaning one well-timed wash covers most of the year.
• Adds measurable resale value. If you’re listing in spring, a fresh exterior is one of the highest-ROI moves you can make. More on the dollars-and-cents of that here.
• Reduces indoor allergens. Cleaning window screens, eaves, and entry areas reduces how much pollen tracks indoors — meaningful relief if anyone in your house has cedar fever.

Frequently asked questions

When does cedar pollen season actually end in Austin?

Mountain Cedar pollen typically tapers off by late February or early March, though sporadic releases can continue into mid-March depending on weather. Pollen counts above 1,000 grains per cubic meter are common through January and early February — for context, anything over 200 is considered “very high.”

Why does cedar pollen stick to my house instead of blowing away?

Cedar pollen contains proteins that become tacky when wet. Overnight dew, morning humidity, and Austin’s frequent winter rains rehydrate the pollen and bond it to porous surfaces like stucco, siding paint, concrete, and wood. Once dry, that bond is hard to rinse off without proper cleaning.

Can I just wait for rain to wash the pollen off?

No — and rain often makes the staining worse. Light rain rehydrates pollen and helps it spread and bond more thoroughly to surfaces. Heavy rain washes some away but leaves a film and can wash pollen-laden runoff into porous concrete where it stains permanently. A proper spring wash with the right detergents is the only reliable fix.

Should I wash my house during cedar season or wait until after?

Wait, unless you have a specific reason (listing the home, hosting an event, allergy concerns). Washing in mid-pollen season usually means you’ll need to do it again within weeks. Late March through early May is the high-value window for Central Texas.

Does cedar pollen damage roofs?

Indirectly, yes. Cedar pollen is organic matter that feeds Gloeocapsa magma — the cyanobacteria responsible for the dark streaks on shingle roofs. Heavy pollen years often correlate with worse roof streaking by the following summer.

Is cedar pollen the only pollen problem for Austin homes?

No — oak pollen follows cedar in late February through April, and pecan and grass pollens take over in late spring and summer. Cedar is the worst because of its volume and timing, but most Austin homes need a single thorough spring wash to address the cumulative load.