No, mandevillas poisonous to touch is not quite the right way to put it. The plant itself won't hurt you just by brushing against it. But the milky white sap inside the stems and leaves can irritate your skin if you break the plant tissue while pruning or handling it. The sap is a mild irritant, not a strong poison, and a quick wash with soap and water takes care of any reaction.
I found this out the hard way during my first spring pruning session. I cut back several stems without gloves and got the milky sap all over my fingers. Within an hour my hands felt itchy and a few small red bumps showed up on my skin. I washed with warm soapy water and the itching stopped within 20 minutes. Since then I always wear garden gloves when I prune or repot my mandevilla.
This reaction traces back to the plant's family tree. Mandevilla sits in the dogbane family along with much more toxic plants like oleander. Mandevilla toxicity is much milder than those harmful plants. Oleander can cause serious harm to people and animals. Mandevilla sap just makes your skin itchy and red for a short time. The family link sounds scary but the actual risk from your vine is quite low.
The ASPCA does not list mandevilla as toxic to dogs or cats. This is good news if you have pets around your garden or patio. That said, UF/IFAS Extension notes the milky sap is a skin irritant and can cause stomach upset if eaten in large amounts. Your pets would have to chew through a lot of plant material for this to become a concern. Most animals leave the vine alone after one taste because the sap is bitter.
Small children should stay away from the sap as well. Their skin is more sensitive than yours and the irritation may last longer. Keep your vine on a high shelf or raised planter where little hands can't reach the stems. If your child does get sap on their skin, wash the area right away with soap and water. Call your doctor if redness or itching lasts more than a few hours.
You can avoid mandevilla sap irritation with a few basic habits. Wear gloves every time you prune, repot, or handle the vine in any way that might break the stems. Nitrile or rubber gloves work better than cloth ones because the sap can soak through fabric. Keep a bucket of soapy water near your work area so you can wash your hands and tools right after you finish. I keep a pair of nitrile gloves in my garden caddy so they're always ready when I need them.
Clean your pruning shears after each use to remove dried sap from the blades. This keeps the sap from getting on your hands the next time you pick up the tool. Wipe the blades with rubbing alcohol to both clean and sterilize them. This step also helps prevent spreading any plant diseases between cuts.
Your mandevilla is a safe plant to grow in your garden as long as you handle it with basic care. The sap causes mild skin irritation at worst and won't poison you or your pets through casual contact. Wear gloves during pruning and wash up right after you're done working with the plant. You'll enjoy years of beautiful blooms without any trouble from this tropical vine. Don't let the sap issue scare you away from one of the best flowering vines you can grow.
Read the full article: Mandevilla Plant Care and Growing Guide
