When most individuals think about cockroaches, they recall images of filthy and germ-infested critters scurrying across surfaces within the house.
However, not all cockroaches reside in houses. These invertebrates exhibit no preference for one location over another and will scavenge wherever there is an abundance of food.
Various types of cockroaches actually prefer an outdoor habitat where they can live in filth, dirt and debris.
Outdoor roach infestations can quickly turn into indoor roach infestations, which means that garden roach control should be a top priority.
Why Do You Have Cockroaches in Your Garden?
There are three main reasons why you’ll see a cockroach infestation within your yard.
Cockroaches, like every other animal on the planet, are seeking food, water, and a place to live.
If you find roaches in the garden, you are likely giving them a mixture of all three in some capacity – which is usually down to the poor upkeep of a garden;
Gardens and yards are perfect environments for the next cockroach meal. This could include decaying organic matter such as leaves and compost, spilled food from a garbage bag, or other dead insects or animals.
If your yard is dirty and not cleaned regularly, you are creating a perfect environment for the cockroaches to find their food source.
Roaches require water as much as they need food and shelter. They will seek out wet and damp areas to rehydrate and breed,
A wet garden, because of clogged catch basins, overwatering sprinklers, and potholes with water, will be perfect to sustain the cockroach population.
Cockroaches are nocturnal, so most activity takes place at night when they emerge to eat, although during the day they will generally be hiding in their refuge.
Cockroaches hide in cracks and holes in the walls, within stones, around woodpiles, catch basins, and even beneath plant pots.
They seek food and new hiding places during the night. That’s when they can sneak into your property undetected.
Some common yard hiding places for cockroaches can include;
Old piles of firewood – rotting wood is a common hiding place for cockroaches
Garbage cans – obvious but often overlooked, a trash can is easy to access for a cockroach, and they can eat through the plastic bags to access the food inside whilst using it as a hiding place
Flowerpots – even if you have a clean garden, cockroaches will still infest the cracks of flower pots brought inside your home by visiting friends or relatives
Flowerbeds – in sheltered areas under flowers and shrubs, especially in mulch
Catch basins & damp areas – these are often filled with water that attracts cockroaches to crawl into them and lay eggs amongst damp debris and waste.
Tree trunks – roaches will surround the base of a tree and take shelter underneath its bark or any loose debris.
Compost pile/decaying leaves – if there are dead leaves or compost in your garden, you will have cockroaches roaming around the area
If you have a few of these hiding places in your garden, you’ll want to ensure they are cleaned often or removed so they don’t become breeding grounds for more pests.
Types of Cockroaches in Your Garden
There are many different types of cockroach that prefer an outdoor habitat over a human dwelling – here are just some common examples;
Often found in basements, garages, and sewers but they will also infest the yard including the flowerbeds.
The American cockroach is the largest species of cockroach encountered in the United States, reaching a length of up to 2 inches. It has a reddish-brown color with a yellow figure-eight pattern on its head and may live anywhere from three months to five years.
Compost heaps, trash cans and garbage mounds, moist regions and around water sources, mulch and decaying plant material in sewers, woodpiles and pet feeding spots are some of the popular outdoor locations.
Brownbanded cockroaches are named for their two light-colored bands across the wings and abdomen. They reach about half an inch in length and have a dark brown or black color and yellow and tan markings on their back.
The male adults can fly to infest different areas of the yard when food is scarce.
Brownbanded cockroaches prefer to live in damp places such as sewer systems, rotting leaves and mulch piles, or dark areas such as under leaf litter, bark or rocks. However, they also inhabit the inside of homes all over the world, so a yard infestation could also mean home infestation.
Smoky Brown Cockroaches
The Smokeybrown cockroach is dark brown or mahogany in color and glossy, and it lacks the distinctive yellow markings on its head, making it resemble an American roach.
This type of cockroach is so named for the smokey brown color of its pronotum and long, smoky-brown wings. The males have a distinct dark spot on the head and the females have an oval-shaped abdomen. These cockroaches live outdoors in mulch and organic matter like woodpiles and under rocks or logs.
They spend most of the daylight hours hiding in logs, hollow trees and decaying vegetation. They also live inside walls and cupboards near food supplies where they can hide during the day.
Males are flighty and will fly long distances to reach a new food source or a female companion. This is why many homeowners notice an infestation when the weather gets warmer in the spring and summer months.
Oriental cockroaches are also called “waterbugs” because they like to live in moist areas near water sources. This type of roach is tan or mahogany in color and about 1 inch long with two dark parallel lines running down the middle of its thorax. It has wings but can’t fly, so it spends most of its time crawling.
Oriental cockroaches like to live in damp, humid areas such as drainpipes, sewers, and garbage disposals. They also hide under rocks or woodpiles and inside basements and crawl spaces.
They are one of the filthiest roaches due to their noxious odor.
Cockroaches in Greenhouses & Glasshouses
Cockroaches can become a real pest when they find a greenhouse or glasshouse in your garden. Native European cockroach species are small and of no importance as pests but four larger species have been introduced from warmer climates and are now well established in heated glasshouses and in bakeries, kitchens and other warm buildings. Of these, the Australian cockroach, Periplaneta australasiae, is the species most likely to damage plants in glasshouses.
They will chew on and eat seedlings and destroy and roots, stems, leaves and flowers of older plants. Cinerarias, chrysanthemums, pot cyclamen, nicotianas, orchids, and schizanthus are particularly prone to attack but many other glasshouse plants may also be damaged, especially when populations of cockroaches are high. Most damage is done at night and the presence of cockroaches can usually be confirmed by inspecting glasshouses 2-3 hours after sunset.
Cockroaches hide during the day in plant debris, pipe ducts, crevices in walls and woodwork, under pots and seed trays and in soil. They come out to feed at night and eat almost any organic matter. They seldom fly but run quickly and erratically. Females lay eggs in tough, brown purse-like cases (oothecae) which are either deposited on the ground or carried by females until the eggs hatch. Each female produces up to 30 oothecae over 3-12 months and each contains about 15 eggs. Eggs usually hatch in 1-3 months at high temperatures but may not hatch for a year or more at low temperatures. Young cockroaches resemble adults but lack wings and wing cases. They take 9-12 months to mature and develop most rapidly above 2I°C (70°F).
How to Get Rid of Cockroaches in Your Garden/Yard
Here are some steps you can take to rid your garden of cockroaches and prevent a further invasion;
Tidy Your Yard
Turn over piles of mulch or soil to expose hiding places. Move firewood, old lawn furniture and any other items that have been left outside for some time into a shed or garage. Keep garages, sheds and outbuildings clean and tidy. Clean up any trash or debris in the yard where roaches can find a safe place to hide.
Eliminate Sources of Water
Remove any potential sources of water around the yard, such as upturned flower pots, watering cans, or buckets. Repair any leaking faucets or hoses. Fill in low-lying areas that retain water and keep the gutters clean. Lastly, only water the lawn in the morning hours so that it has time to dry.
Eliminate Sources of Food
Keep your garbage cans tightly closed and take the trash out regularly. Clean up any food spills in the yard or compost pile immediately. Pets’ food dishes should be replaced on a daily basis.
Protect Your Home
Cockroaches may be present in your garden because close by is an easy route to inside your home, via a crack or hole in a wall.
Around the outside of your property, fill in any cracks and voids with sealant to keep an adult roach from entering.
Proactive Elimination of Cockroaches
If you have a visible cockroach infestation in your garden, the above steps will help to deter them but you must remove the cockroaches that are currently present.
The best way to get rid of cockroaches in your garden are:
Cockroaches are scavengers and will eat just about anything. They are lured to bait stations that contain a food source mixed with boric acid or other similar active ingredient. Bait stations should be placed in areas where cockroaches have been seen, but should not be seen by children or pets. Baits must be used with caution around plants as plants can absorb the active ingredient.
Remember to always read and follow any specific safety information provided on a product label before using a pesticide for domestic use.
Pyrethroid insecticides are very effective for cockroach control, even when they are inside walls or other hard-to-reach places. These products should be sprayed directly onto the insects and should not be allowed to build up on surfaces where they can harm beneficial insects.
Be sure to read and follow all the instructions and restrictions provided on a pesticide label before using it.
Roach motels or sticky tape
Roach motels are small, enclosed areas containing food for the roaches. The insects walk through a glue area and get stuck to it making them easy prey for predators.
To use, apply in out-of-the-way places where you have seen cockroaches in your yard. These products can be used on some hard surfaces, such as countertops and window sills, but should not be used around food preparation areas. They will also need to be moved regularly as roaches leave and enter the treated area.
Sticky tape is a non-toxic product that works on the same principle as a roach motel. The sticky surface traps the insects as they walk across. Replace as necessary.
Gel-based insecticides are a convenient way to kill cockroaches, as you simply apply the gel onto cracks and crevices where the insects hide. Ensure that you keep all children and pets out of the treatment area until the gel has dried.
Remove Roches From your Greenhouse/Glasshouse
Cockroaches are usually most troublesome in old glasshouses run at high temperatures as these usually contain plenty of food and cover and therefore good conditions for rapid breeding.
Limit potential breeding by removing accumulations of rubbish and by repairing old brickwork and woodwork.
Diatomaceous earth is the best line of defense. This non-toxic powder is composed of crushed fossilized seashells. The sharp dust irritates the insects’ bodies, causing dehydration and death.
Apply diatomaceous earth with a pest control duster or power duster to pipe ducts, paths, brickwork and other surfaces on which cockroaches will walk at night and renew at intervals of a week or so until the population is reduced.
Baits of bran, bread, beer, sugar, treacles and various other materials can be used to trap cockroaches in jars or wide-mouthed bottles sunk flush with the soil surface. A little bait in the bottom of each container attracts cockroaches which fall in and are then unable to scramble out.
Insecticide may be mixed with bait or trapped cockroaches may be killed by pouring very hot water into containers. Persistent trapping for a few weeks will give good control but eggs may continue to hatch for up to a year and repeated trapping may be necessary.
Remember, prevention is key. Keeping your garden as clean as possible and limiting hiding places for roaches will help to keep them away.
There are control options such as baiting, sprays, or sticky strips that can be used in your yard if necessary.
As insects go, cockroaches get a pretty bad rap. They can be annoying and unsanitary to have around the house or garden. However, they are only doing what comes naturally to them in search of food and shelter. If you make it more difficult for them by limiting their access to these things they will soon move on elsewhere.