Spiders in the Garden (And Why We Love Them!)

A quick note before we begin: This blog is intended for audiences in the United States and Canada. International readers will likely have different species of spiders, which raise different concerns—we’re looking at you, Australia. Please learn about your local species of insects, arachnids, and wildlife and interact with them in a way that is both safe for you and respectful of them.

Spiders—we use them as Halloween décor for a reason. They’re alien-looking from a human point of view, they inhabit webs in disused corners and other “creepy” places, and many of us are afraid of them. The reality is that most species of spider we’ll encounter in North America are pretty harmless and are actually beneficial to home and garden. By learning more about spiders and the ecological niches they fill, we can take away the irrational fear and replace it with respect and reasonable caution. So, let’s dig in and learn a bit more about spiders in the garden and why we love them!

Are Spiders Dangerous?

Generally speaking, the spiders we’ll encounter in homes and gardens across North America aren’t dangerous. While all spiders may bite if they feel threatened, there are only a few truly venomous North American species.  That having been said, some folks do have allergic reactions to non-venomous spider bites and it is best to treat all spiders with care. There are two venomous spiders that are relatively common across the US and Canada, and we need to be aware of them:

· The Black Widow Spider (Latrodectus spp) is a family of closely related species that are found across the US and Latin America and into parts of Canada. These are typically medium-sized, a shiney black color, and easily identified by a red, hourglass shaped marking on their backs. They like to build nest in out-of-the-way spaces like sheds, closets, bushes, and overgrown areas.  Black widow venom can cause bad reactions, with symptoms like difficulty breathing, nausea, fever, pain and inflammation, and even convulsions. A bite is unlikely to be fatal in an adult but could be quite dangerous for a child, so any black widow bite should be treated medically as quickly as possible.

· The Brown Recluse Spider (Loxosceles reclusa) is mostly found in the central and southern US. A small brown spider, it is as the name suggests quite reclusive and prefers to build its webs in undisturbed places like woodpiles, attics and basements, and other low-traffic zones. While small Brown Recluse spider are easily identified by their brown color, long legs for their size, and a mark on their heads shaped like a violin. While non-aggressive, the venom can result in serious symptoms including tissue necrosis so medical treatment is a must for any Brown Recluse bite.

Again, other North American spiders can deliver nasty bites which may cause reactions in some folks, so please approach all spiders with respect and caution.

Common Non-Venomous Spiders

Now we move on to the fun part—meeting some of the non-venomous spiders that we may encounter in our gardens. There are a dazzling variety of spiders found across the US and Canada, and we don’t have the space to list them all here so instead we’ll introduce you to some of the most common that you might see in your garden.

· Wolf Spiders (Lycosidae spp) are common throughout the USA and the border provinces of Canada. These are large-ish spiders, generally, with a brown fuzzy coloration that can be striped in some species. Unlike many spiders, Wolf spiders don’t build webs, but instead hunt their prey using their sharp eyesight and sharp reflexes. This makes them a great addition to the garden—they help keep pests and insect populations in check. While Wolf Spiders will bite if provoked, they’re not considered dangerous to humans so just treat them with a bit of caution and give them space as needed.

· Orb Weavers aren’t really a single species or family, but a collection of species that all exhibit a similar trademark behavior: building huge and beautiful webs! The spiders themselves range in size from the tiny Spineybacked Orb Weaver (Gasteracantha canreiformis) to the much larger Golden Orb Weaver, also known as the Banana Spider (Trichonephila clavipes). While the latter may look both beautiful and scary, they’re harmless to humans and their huge webs are both beautiful and useful in reducing unwanted insect populations. So, as always, give them space and enjoy the beautiful webs they create!

· The Yellow Garden Spider (Argiope aurantia), also known as the Black and Yellow Garden Spider, is a medium sized spider found in homes and gardens across the US and in parts of Canada. Typically around 1 inch/2.5 cm in size with a distinct and striking black and yellow coloration, they build large webs like their Orb Weaver compatriots. Unlike many species, they will build webs in the daytime, and if a larger creature (like a gardener!) approaches they’ll shake their webs vigorously in order to prevent a collision. Never fear, however, Yellow Garden Spiders are non-aggressive and not at all dangerous to humans though they will bite if grabbed or otherwise disrupted.

· And finally, because we knew you’d ask: The Tarantula! While there are many species of Tarantula found around the world, these large hairy spiders are an iconic feature of the American Southwest and northern Mexico—sorry Canada, but as far as we know you have no native tarantula species. The most common US tarantula species is Aphonopelma hentzi, also known as the Texas Tarantula, the Brown Tarantula, or the Oklahoma Tarantula. Ranging from Missouri through Kansas, Oklahoma, Texas, and across the Southwest and northern Mexico, these large furry spiders are generally non-aggressive to humans. They feed on smaller insect, and may build tunnels to nest in.

There are so many more species of spiders—we could fill a year’s worth of blogs with them—but these are the most common or iconic North American species that you may encounter. Again, with some exceptions the spiders found in the US and Canada aren’t dangerous to humans, but all spiders should be treated with respect and a bit of caution. They’re wonderful additions to our gardens, so let’s take the fear away from spiders and replace with with curiousity and knowledge!