Why Won't These Tree Roaches Go Away?

Peacock Pest Prevention Blog – November 2025 By Lisa Botts, CA, A.C.E, Owner

Ah the cooler Houston evenings, when you can finally sit on your porch, flick on those beautiful Edison lights and get dive bombed by a flying cockroach that looks like a holdover from Jurassic Park.  Welcome to Houston, where smokybrown roaches (Periplaneta fuliginosa) and American roaches (Periplaneta americana) treat your landscaping like an all-you-can-eat buffet—and your lights attract them like moths.

These aren’t your kitchen-cabinet German roaches. These are peridomestic tree-dwellers that fly in from oak canopies, gutter debris, and your mulch. One heavy rain and they’re marching indoors faster than you can say “Whataburger at 2 a.m.”

Understanding a little more about peridomestic roaches can help us combat them.  These roaches prefer to be outside, where the moisture fits their preferences; but they can live inside if the conditions are conducive.  Houston has 90% humidity with 50 inches of rain annually.  Our mulch and landscaped areas stay damp.  Piling up mulch to your siding and storing wood or other objects against the home can provide dark damp places for roaches to live and breed.  Then when your mulch starts to decay and break down, fungi and bacteria help that process along and that feeds the roaches. 

Not so fun fact:  A single female can drop 30 egg cases in her lifetime, each of those can hatch 30 to 40 babies.  one female = 30 eggs cases x 35 babies = 1,0505 roaches.

So how can you help reduce the roaches trying to fly at you?

First, replace mulch against the home with river rock or pea gravel to reduce moisture retention and food sources.  If you create a 12-inch “moat” around the foundation, not only does it help to reduce roaches, but it makes it easier to see mud tubes for termites and reduces the need to reapply mulch annually.

Second, if you do use mulch, use cedar chip mulch.  The natural oils in cedar help repel roaches and termites.  It drains faster in our flash flooding and only needs to be refreshed every two years – remove the old layer first.  Piling new on old = a roach layer cake.

Our third tip, which is a little more expensive, is to use lava rock or decomposed granite.  This will give your yard a unique look.  The rocks are heat-reflective, which makes roaches miserable.  There is no organic matter at all, so no food source.

Finally, clean your gutters!  You would be surprised how many pests count on the gunk and water that build up in those gutters for their food, water and harborage.

Cockroaches don’t take winter breaks in Houston. November’s cooler nights just drive them inside for warmth, food and water.

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Peacock Pest Prevention, LLC – Houston’s local, family-owned pest pros since 2017. We Kill What’s Bugging You.