This week I prepared a lesson on cacti for my garden club students. It’s a great lesson for the February or anytime in the winter, as it can be conducted inside. So many of our days have been sub-zero this year, it was proactive thinking to have a lesson that didn’t include being out-of-doors.
Teaching on cacti and succulents has been on of my favorite lessons over the years. I started including this topic the year we did a theme on plant adaptations for all of our monthly topics. I’ve long been interested in cactus, and especially the prickly pear.
Prickly pears or Opuntia have the largest genus of all cacti with over 360 species. But, that is not what interests me. What I find really fascinating is that they grow all over the world. Even in Wisconsin, they can survive our typical cold and snowy winters. This year, might prove to be an exception. As I prepared my lesson for the other day, I learned that they can withstand temperatures of up to -30 degrees. We’ve pushed that window, so time will tell, as we begin spring hikes.
A neighbor up the street has a prickly pear in their front yard. And, it is said that the protected sand prairie in our town has prickly pears growing there as well. Although, I have never seen them. Perhaps, it is because I stayed on the trail and did not go off to hunt them down.
I’ve noted prickly pear cacti almost everywhere I’ve travelled. They can be found on the island of Bermuda, especially on the grounds of the old Royal Dockyard site. I’ve seen them in the San Diego area – growing everywhere along side the road, and especially in Balboa Park. Mexico can claim these plants as part of their natural cultural heritage, where even in the Southwestern United States they are sold and eaten, once cleaned and the spines removed. Larger plants flower and leave fruits that are edible as well.
As with most cacti, once they are established their growing habits are relatively easy and survive on benign neglect. They tolerate heat and drought, unless they are a newly germinated seed, which needs moisture and high humidity.
These plants are most easily propagated with cuttings, but handling the tiny spines that are difficult to remove once imbedded in skin is something I definitely wanted to stay away from with my students. So, I bought seeds from a local nursery specializing in native plants. It was part of my lesson on Thursday to plant the seeds with my students.
Unfortunately, we are having a winter of cancellations due to inclement weather. Garden Club was cancelled with all of the other after school activities on Thursday. My cactus lesson will have to wait. Back in the refrigerator went the seeds and back in the closet went my bag of supplies. I’m sure we’ll still be having winter in March, so I will just use this lesson at that meeting.
The students will be awed at how cacti grow using all their adaptations, from the waxy coating on the stems (true cacti have no leaves) to the shading function of the spines that virtually no one suspects as their use. Cactuses capacity to generate instant roots to absorb a rare desert rainfall and the plant’s ability to then store water by swelling to many times its dehydrated size, are all awe-inspiring facts I love to share with the students.
Yes, there will be time for our prickly pear lesson. Students will be surprised to learn that not all cactus live in the desert.
Now, if we can just get rid of this snow!