Yellow-Green Pollen Film on Siding in Spring

When Kentucky pollen season runs

Family Allergy and Asthma, a Kentucky allergy practice, lays out the tree season like this (Family Allergy and Asthma):

• Trees often start pollinating as early as February. A long, cold winter can push that back a few weeks into early March.
• Oak and cedar start in February or early March.
• Willow, pine, birch and mulberry pollinate in April.
• Tree pollen falls off around mid June.

That is a long window, and it lines up with the time most people start looking at the outside of their house again.

Why it sticks

Pollen does not land alone. It settles on walls, decks and drives along with the dust and dirt already there, and on damp, shaded surfaces it stays put.

That film matters for more than looks. University of Maryland Extension experts point out that algae on outdoor surfaces feeds on the nutrients in dust and particles that settle there (Ask Extension, 2019). A wall that collects a spring of pollen and dirt can give algae more to grow on. The green version is covered in green film on vinyl siding.

How we clean it off

On siding, we use the same soft wash as any house wash: low pressure and a professional grade cleaning solution, so the film comes off without water being forced behind the panels. Decks are cleaned at the pressure the boards can take, and driveways and walkways get high pressure cold water like any flatwork.

When to book

There is no wrong time, but there are two good ones:

1. Early in the season, if the house is already green from winter and you want it clean going into spring.
2. After the heaviest tree pollen, toward late spring, if you want one wash that stays clean longer.

Spring is the busiest time of year for exterior cleaning, so booking early gets you the date you want.