Plants Dangerous to Humans?


Note : Sorry for the English :/

Hi.. Im planning to plant air-purifying plants and some pretty flowering plants for my old school.

I choose:

The Air Purifiers :

– Draceana “song of india”
– Sansevieria trifasciata “snake plant / mother in laws tongue”
– chlorophytum comosum “Spider plants”
– tradescantia zebrina ” spiderwort / wandering jews “
– Aloe vera.

The pretty bloom plants :

– Thunbergia alata “black eyed susan vine”
– Gardenia augusta “gardenia flower”
– Blue butterfly Pea

Or is there other thats better?

I can only plant safe ones ( Very safe ones ( nontoxic! ) ) because the school is filled with Kids! Kids everywhere, running, playing, messing the place too :P they sometimes destroy plants (accidently or in purpose), and the plant sap will go on their hands. Im affraid that they might Lick the sap from their hands, or Eat something without washing their hands! ( or did but not washing it properly )… The worst thing i thought that a nibble-loving child ate one of the plant! :(( i want to add splashes of colour and also clean some of the air in the school, not poisoning kids! So safe plants is very needed just in case if a child “accidently” consumed a plant part from the plant i planted there :O theres lots of safe plants ( veggies, dandelion, marigolds, sunflowers ) BUT! The place is shady, very shady! Thats why i choose the Draceana, snake plants, spider plants and spider worts ( google said they can handle shade ) i also googled all of them if they are poisonous, but this sites says yes, that one said a little, this other said nothing, that other said its harmless.
I need a big explanation People!

Heres Some other questions too:

– any of them dangerous / toxic? Because i will remove the one that has dangerous chemical in any part of the plant from the list im planting in the school.

– will Black eyed susan, gardenia, blue butterfly peas and aloe vera grow in shady areas? The place in school im placing the plants gets little sunlight, maybe at around 12 pm it gets filtered sunlight. The rest sunlight is blocked by the school building.

– i will put the spiderwort / wandering jews at the bottom of a ( what is it called? Its like a blower that blows out dirty air / gas from air conditioners. air con machines filter the air, The clean air goes out from air conditioner, the dirty gas waste goes out from that thing ).
Is it okay? Will it die or mutate because of the too much dirty air around the plant.

– sound stupid but someone said that : snake plant, draceanas ( and other i forgot ) release dangerous gas from them at Day time. Like somekind of pestiside or plastic chemical it gets from soil or something… Is it true???
I will read it again soon.

– is it a good idea to do this?

Best Regards



Hi Rhine– When planning any garden project you need to first look at the conditions of the planting site in terms of: hardiness, light, moisture and soil quality. This information will allow you to create a list of plants that will thrive in your situation. From this list you can then select plants that meet your objectives for the project. Sounds to me like you’ve started with some specific objectives and plants in mind and are questioning their suitability for your project for a number of reasons. Take a step back and look first at the area where you plan to locate your project.

I assume that you are in the Toronto area and are planning an outdoor garden in an area that is shaded by the school building. I’m also assuming that you wish to plant perennials, that is, plants that will overwinter rather than annuals which must be replanted every year. Plants that are hardy in the Toronto area will be labelled as zone 6 or lower. (Canada is divided into 9 different hardiness zones according to factors such as lowest temperature of the coldest month, highest temperature of the hottest month, precipitation, number of frost-free days and other factors.)

Make note of how much light your proposed bed does receive. The area is considered full shade if it receives less than 4 hours of sun a day, partial shade if 4 hours of morning or afternoon sun is received and full sun if at least 6 hours of direct sun is received. In terms of moisture, look for indications of how well the area drains. Most plants do best in a well-drained site. Many plants will adapt to a variety of soil conditions but generally prefer soil with a lot of organic matter. If the soil looks hard and cracked, you may need to consider improving the organic matter content over time.

All of this analysis is to determine which plants will not only survive but thrive in your site. For a list of plants suitable for different conditions, have a look at our gardening guide on long blooming perennial plants. Click here to access the guide.

Once you know what characteristics a plant must have to thrive in your site, you can select those plants that meet your objectives for the project. The air purifying plants you’ve listed are all indoor plants although some can be treated as annuals. For example, spider plants (Chlorophytum comosum) and spiderwort (Tradescantia zebrina) are often used in outdoor container arrangements. There has been a lot of information lately particularly the research conducted by NASA on plants that can contribute to the quality of the air in our homes. All of the plants you’ve listed are good examples of air purifying plants but they will not survive outdoors. An earlier post on our website, provides more information on indoor purifying plants. I’ve included a link to the post below.

As you suspected, all but one are poisonous although spider plants have only minor toxicity and Dracena is toxic to dogs and cats but not to humans. I’m including below a link to a recent article on 200 Poisonous House Plants from garden blogger, Larry Hodgson which I found a good source for this information.

Outdoors, the trees are our great air purifiers improving air quality by trapping pollution particles that cause breathing problems and absorbing carbon dioxide and other gases and in return providing oxygen. Is there an opportunity to plant a tree in your school yard?

You should be able to find a selection of flowering plants that will thrive in your site. The ones you have listed are all tender plants that will not survive winters in our area. Black eyed susan vine (Thunbergia alata) is frequently grown here as an annual providing lots of summer colour but dying with the first frost. First check that any plant you are considering is hardy to zone 6 or lower. Next select only those plants that thrive in part to full shade. Another of our gardening guides, Drought Tolerant Perennials provides lists of perennials based on their light requirements. Click here to access the guide. I have a lot of shade in my garden and one of my favourites is perennial geranium. I particularly like bigroot geranium (Geranium macrorrhizum) which will thrive in dry shade. As an added bonus, the leaves provide good fall colour.

I hope this information will help with your garden planning. Contact us again if you have other questions or if you’d like additional suggestions for plants that will thrive in your conditions.

200 Poisonous House Plants

Scrubber Plants