Plant Protection! The Smart Ways Plants Stay Safe

Being a plant is not easy. Many animals eat leaves as food, but plants need their leaves to capture sunlight. Plants can’t make the energy they use to live and grow without sunlight. They must keep their leaves safe, but plants are rooted to the ground. They can’t run away from a hungry animal. So what’s a plant to do? Come up with a defense!

Ouch!

Some plants protect themselves by growing a sort of sharp armor. The sharp parts have different names depending on how and where they grow on the plant. Thorns are a kind of branch. Locust trees are one of the best thorn-makers. Their thorns may be up to three inches (7.6 cm) long! Roses don’t have thorns. Their sharp parts are called prickles. Prickles aren’t thorns because they come from the rose’s skin and not from branches. Cacti grow spines on their leaves. Some plants, such as thistles, have hair-like bristles. It doesn’t matter what these sharp parts are called. They all make these plants too painful to eat for many animals.

Yuck!

Plants take minerals from the soil and change some into chemicals they can use. These can act as poisons that make creatures sick or even harm them. Mustard plants use them to make their leaves taste bad to hungry caterpillars. Foxgloves have a strong poison. It can cause a heart attack if too much of the plant is eaten. That’s why animals such as deer and cows leave foxgloves alone. Coffee plants have caffeine for the same reason. Too much makes bugs sick. They know not to take a bite. Chrysanthemums (say kruh SAN thuh muhmz) make a poison that kills insects. Some gardeners even use sprays made from chrysanthemum flowers to keep bugs off their plants.

Help!

Some plants use their chemicals to call for help. Maize lets out a smell when it’s under attack. The smell brings wasps that feed on other bugs. The wasps fly in and eat up all the insects. This saves the maize. One kind of tobacco plant attracts wasps the same way if it’s being eaten. Peony flowers trade food for protection. They make a sweet nectar for ants. The ants drink the nectar, but they don’t harm the plant. The ants don’t want other insects near their food, so they chase the rest of the bugs away. The ants get a meal, and the peonies use the ants as guards.

Fooled You!

Some plants have tricky ways to protect themselves. Dead nettles look like stinging nettles, right down to the hairs on their leaves and stems. In a stinging nettle, those hairs are full of poison. But a dead nettle has no poison. Its hairs are a trick. The sensitive plant has another trick. It folds up its leaves when touched. The folded leaves make it look like the plant is dead and not good to eat. The pebble plant looks like a small rock. It hides by growing next to real rocks on the desert floor where it lives.

Plants may not be able to run away from danger, but their clever defenses help keep them safe.